改革开放40多年来，中国城镇化迅速发展，经济增长实现了质的飞跃。在当前经济形势下，城市作为中国发展经济的载体，需要着重解决内在的深层次矛盾来实现高质量增长。当前，中国城市发展面临着内外两方面的约束和挑战，从内部看，城市的资源环境承载力已经逼近极限，经济增长的新旧动能亟待转换；从外部看，中国城市发展面临着新一轮技术革命与全球化发展带来的新挑战。因此，要想破解中国城市发展的资源环境约束并提升城市的竞争力，本质上要求确立以城市群作为城市化最高的空间组织进行发展，通过协调发展要素，促使生产要素自由流动、资源优化配置，推动我国经济长期稳定增长。基于此，本文抓住中国国家级城市群增长这一核心问题，遵循“理论分析→测度评价→实证检验→战略对策”的研究思路，对城市群增长的内在机理以及中国国家级城市群增长的动力机制与影响因素、空间增长效应和未来前景进行深入考察与分析。

    本文首先对现有研究城市群增长的相关理论进行梳理，并借助Cobb-Douglas生产函数以及内生增长理论，将技术创新和城市集聚纳入到熊彼特产品垂直框架下的内生增长模型中，并从技术资本和智力资本两个维度进行推导，探讨在技术内生化后，技术资本以及智力资本的积累能否取代物质资本进而成为推动城市群实现长期增长的主要动力。依据理论推导结果形成了城市群增长的一般理论模型。同时，本文从城市群的静态增长到动态增长两个方面对城市群增长的资本投入和实际产出关系进行了综合性探讨，最终形成了城市群增长的分析框架。

    其次，本文基于2008—2017年中国14个国家级城市群202个地级市面板数据，以技术进步对经济增长的影响为研究主线，运用方向性距离函数以及ML生产率指数测度了14个国家级城市群的全要素生产率，对城市群的增长水平进行了科学测度。研究发现，国家级城市群全要素生产率平均增长8.1%，增长的主要动力来源于综合技术进步，贡献度达到9.3%。从空间和地区差异来看，东部地区城市群全要素生产率年均可以增长1.6%，技术效率年均可以增长0.65%，技术进步年均可以增长0.96%；中部城市群由于技术效率倒退了0.85%，导致全要素生产率增长低于东部地区的现象；西部城市群同样也是因为技术效率的下降影响了全要素生产率的提升。本文又进一步通过GMM动态面板模型探讨了城市群增长的动力机制和影响因素。研究发现，从驱动因素看，技术投入的增加、周边城市与城市群整体经济发展差距缩小、城市集聚度的增强有助于提升城市群的经济增长率，促使城市群产生良好的增长效应，但是城市集聚并未产生良好的疏解效应，无法完全疏解聚集的不经济；外来直接投资增加可以促进城市群整体的经济增长；人力资本的积累也会促进城市群产生良好的增长效应。从影响因素看，行政壁垒的存在会阻碍城市群的集聚与发展，还会影响FDI投资规模、产业结构的升级与人力资本的积累，不利于城市群的增长；空间结构也对城市群增长产生显著的影响，从东中西分布来看，东部地区城市群拥有较高的技术水平和城市集聚度、较为成熟的人力资本积累以及更为合理的产业结构，经济增长效应最明显；中部地区城市群主要依靠城市间的协同合作发展实现经济增长；西部城市群基础设施较差、发展水平较低，技术、城市集聚度、人力资本积累以及产业结构均较为落后，没有产生良好的增长效应。研究还发现，从南北方分布来看，南方地区城市群技术创新发展较好、经济梯度差较小、城市集群度高，并且拥有较为完整的外来投资结构、产业结构，经济增长较快；北方地区城市群主要靠人力资本积累来实现经济稳定增长；从不同核心城市的城市群发展来看，拥有两个以上的多核心城市的城市群拥有较好的技术发展水平，城市间经济发展差距较小，城市集群度较高，在发展经济过程中形成了一种相互促进、相互支撑的模式，各个核心城市的职能分工在发展区域经济过程中形成了互补，在竞争中促进了城市群经济的增长。本文又通过门槛面板模型分析了核心城市可达性对城市群增长的影响，结果表明城市群内其他城市与核心城市可达性在116.1公里以内有利于产生较好的增长效应；当城市群内其他城市距离核心城市距离在116.1公里—349.55公里时，城市群内经济发展差距进一步扩大，不利于城市群产生良好的增长效应；城市群的增长效应随着核心城市可达性的延长经历了“逐步减弱——恶化——得到改善”三个阶段，城市群经济梯度值与核心城市可达性呈倒“N”型关系。

    基于城市群间在空间上存在显著的经济相连和空间相关性，本文又进一步对城市群增长产生的空间效应进行了测度。结果发现，国家级城市群经济增长在空间地理上存在显著的经济相连及空间关联特性，即空间相邻城市群的经济增长会显著促进本城市群经济增长。在空间假设下，技术投入的增加以及城市经济发展差距缩小，城市集聚度的增加、产业结构升级均对城市群整体的经济增长产生正向影响。同时，外来直接投资、人力资本在地理空间上表现出了显著的相关性，并产生了正的外溢效应；从传导机制看，城市集聚度的提升，促进了技术投入的增加、外来投资结构的优化、人力资本的积累，使得城市群经济出现显著增长，但集聚度增加对产业结构升级影响不明显。

最后，在总结理论和实证研究结果的基础上，本文从推进制度改革与建设、增强自主创新能力、优化城市群内部发展结构、深化区域合作、培育高质量发展理念五大方面提出了新时代中国城市群增长的对策建议。

    本文的亮点在于，将城市的内生增长与高质量发展问题的讨论引至城市群层面，尤其在国家对城市群发展提出了更高要求后，论证了城市群增长、资源环境约束和经济发展效用“三位一体”实现的可能，丰富了城市群增长的理论研究；本文结合DEA、OLS、动态GMM、门槛面板等多种实证方法，多角度、全方位对国家级城市群的增长进行了测度与校验，改善了传统研究城市群增长的片面性；通过空间分析14国家级城市群的增长，探究国家级城市群空间增长最优路径，有效拓展了研究城市群增长的思路，为14个国家级城市群增长战略的制定提供可资借鉴的依据。

    Over past 40 years of reform and opening up, China has witnessed rapid urbanization and a qualitative leap in economic growth. In this current economic situation, as the carrier of China's economic development, cities need to focus on solving the deep-seated problems to achieve high-quality economic growth. Under the background of the new era, the spatial structure of economic development has undergone profound changes with the deepening of regional economic development. China's urban development faces two aspects of constraint and challenge. From the perspective of domestic, the carrying capacity of the city's resources and environment is approaching the limit, and the new driven forces of economic growth need to be replaced. From the perspective of abroad, China's urban development is facing new challenges brought by a new round of technological revolution and globalization. Therefore, in order to break the resources and environmental constraints of China's urban development and enhance the competitiveness of urbanization development, it is essentially required to establish urban agglomeration as the highest urban spatial organization form, and by coordinating development factors, which could promote the free flow of production factors and optimize the allocation of resources, so as to promote long-term and stable economic growth. However, the current academic research on urban agglomeration growth is relatively scattered, especially lack theoretical research. Based on this, this dissertation holds the core issue of national urban agglomeration growth, and follows the design of "theoretical analysis→ measure and evaluation→ empirical test→ strategic countermeasures" to detect the internal mechanism and influence factors and dynamic mechanism, spatial effect and future prospects of urban growth and national urban agglomeration growth.

    This dissertation summarizes existing researches on relevant urban agglomeration growth theories, and then uses Cobb—Douglas production function and endogenous growth theory to include technology innovation and urban agglomeration in Schumpeter product vertical under the framework of endogenous growth model. The dissertation reasons technology capital and intellectual capital to discuss that if technology capital and intellectual capital accumulated could replace the physical capital and become the main power to promote long-term urban agglomeration growth when technology is endogenous. According to the theoretical result, the general urban agglomeration growth theoretical model is formed. At the same time, this dissertation comprehensively discusses the relationship between capital input and actual output of urban agglomeration growth from static growth to dynamic growth, and finally forms the analysis framework of urban agglomeration growth.

    Secondly, this dissertation uses panel data of 202 prefecture-level cities in 14 state-level city clusters in China from 2008 to 2017, taking the impact of technological progress on economic growth as the main research line, measures total factor productivity of 14 state-level city clusters based on directional distance function and ML productivity index. The research shows that the total factor productivity of state-level city clusters increased by 8.1% on average, and the growth was mainly enhanced by comprehensive technological progress that contributed by 9.3%. From the perspective of spatial and regional differences, total factor productivity in the eastern urban agglomeration can increase by 1.6%, technological efficiency by 0.65%, and technological progress by 0.96%. The growth of total factor productivity in the central urban agglomeration is lower than that in the eastern region due to the 0.85% retrograde of technical efficiency. The decline of technological efficiency in western region also affects the improvement of total factor productivity. This dissertation further uses GMM dynamic panel model to discuss driving and influencing factors on urban agglomeration growth. The results show that, from the perspective of driving factors, the increase of technology input, the narrowing of the overall economic development gap between surrounding cities and urban agglomerations, and the enhancement of urban agglomeration are conducive to improve the economic growth rate of urban agglomerations and the promote good growth effect of urban agglomerations. The increase of foreign direct investment can promote the overall economic growth of urban agglomeration. The accumulation of human capital will also promote urban agglomeration good growth. The promotion of industrial structure has no obvious driving effect on the economic growth of urban agglomeration. From the perspective of influencing factors, the existence of administrative barriers will hinder the agglomeration and development of urban agglomerations, and also affect the scale of FDI investment, the upgrading of industrial structure and the accumulation of human capital, which is not conducive to the growth of urban agglomerations. Spatial structure also has a significant impact on the growth of urban agglomerations. From the perspective of east, center and west distribution, the urban agglomeration in the eastern region has high technical level, urban agglomeration degree, relatively mature human capital accumulation and industrial structure, and the economic growth effect is the most obvious. Urban agglomeration in the central region mainly relies on the coordinated development among cities to achieve economic growth, the infrastructure and development level of urban agglomeration in the western region are poor, and the technology, urban agglomeration degree, human capital accumulation and industrial structure all lag behind, so there is no good growth effect. From the perspective of distribution in the south and north, urban agglomeration in the south enjoys better technological innovation and development, smaller economic echelon difference, and higher degree than urban cluster. Meanwhile, it also has a relatively complete structure of foreign investment and industrial structure, and rapid economic growth. The urban agglomeration in the north mainly relies on the accumulation of human capital to realize the stable economic growth. From different angles of the core city of urban agglomeration development, with two or more than the core city of urban agglomeration has good technical development level, urban economic development gap between small, urban cluster degree is higher, in the process of economic development to form a kind of promote each other, support each other, each core city of functional division formed complementary in the process of regional economic development, promote the growth of the urban agglomeration economy in competition; This paper also analyzes the influence of the accessibility of core cities on the growth of urban agglomeration through the threshold panel model. When the distance between other cities in the urban agglomeration and the core city is between 116.1 km and 349.55 km, the gap of economic development in the urban agglomeration is further widened, which is not conducive to the good growth effect of the urban agglomeration. With the extension of the accessibility of core cities, the growth effect of urban agglomeration has gone through three stages of "gradual weakening -- deterioration -- improvement". The economic gradient value of urban agglomeration has an inverted "N" type relationship with the accessibility of core cities.

    Since the cities of urban agglomerations have significant economic connection and spatial correlation in geographical space, this dissertation further measures the spatial effect of urban agglomeration growths. The result shows that the economic growth of China's state-level urban agglomerations has significant characteristics of economic interconnection and spatial correlation in spatial geography, which means adjacent urban agglomerations economic growth will significantly promote urban agglomerations economic growth. Under the spatial hypothesis, the increase of technology input, the narrowing of urban economic development gap, the increase of urban agglomeration and the upgrading of industrial structure all have positive effects on the overall urban agglomeration economic growth. At the same time, foreign direct investment and human capital show significant correlation in geographical space, and produce positive spillover effect. From the perspective of transmission mechanism, the improvement of urban agglomeration promotes the increase of technological input, the optimization of external investment structure and the accumulation of human capital, resulting in the significant growth of urban agglomeration economy, but the spatial performance of agglomeration degree on industrial structure upgrading is not obvious.

On the basis of summarizing the theory and empirical research, this dissertation puts forward the strategic countermeasures for the growth of urban agglomeration in the new era from five aspects: promoting the reform and construction of the system, enhancing independent innovation, optimizing internal development structure of urban agglomeration, deepening regional cooperation, and cultivating the concept of high-quality development.

    The highlight of this dissertation lies in the fact that bringing the discussion of endogenous growth and high-quality development of cities to the level of urban agglomeration, especially when the state put forward a higher request for urban agglomeration development, this dissertation verify the possibility of uniting urban agglomeration growth, resources and environment constraints, with economic utility. In terms of empirical research, this dissertation uses DEA, OLS, dynamic GMM, threshold panel and spatial empirical methods to measure and verify the pattern and effect of urban agglomeration growth, which improves the one-sided nature of traditional research on urban agglomerations. With the spatial analysis of 14 state-level urban agglomeration growth, this dissertation explores optimal paths for state-level urban agglomeration spatial growth, and effectively expands the train of thoughts on urban agglomeration growth，which will also provide an important basis and reference for the formulation of the growth countermeasure and suggestion of 14 national city clusters in China.