2014年中共中央提出了京津冀协同发展的国家战略，2017年国家正式设立了国家级雄安新区，经过几年的实践探索，雄安新区在疏解非首都功能、推动形成“一核两翼”发展新格局上初有成效。但京津冀协同发展仍存在一些不足和短板，这主要根源于京津冀地区的人口问题。人口规模、老龄化结构和空间布局是经济社会发展的重要内生变量，也是制约京津冀协同一体化的关键因素。在此背景下，科学预测京津冀地区2021-2050年的人口规模和结构的变化规律，分析人口迁移和人口老龄化的趋势，了解京津冀地区未来人口老龄化的时空演化特征，可以促使区域人口空间合理分布，提高应对人口老龄化资源和服务的匹配程度，推动京津冀一体化的高质量协同发展。

本文对京津冀人口的研究工作主要包括三部分，一是基于队列要素法，使用Leslie矩阵建立人口预测模型，并基于第七次人口普查数据对京津冀三地2021-2050年的静态人口做出预测，即人口的内生演化；二是构建了京津冀地区人口迁移复杂系统，通过多主体建模方法，建立了京津冀人口迁移多主体仿真模型。自底向上地模拟人口的迁移过程，展现未来京津冀地区人口流动迁移的变化情况；三是结合人口内生演化和人口迁移，分析未来京津冀地区的人口规模、结构以及老龄化的变化趋势，并考虑雄安新区的政策因素影响，基于多主体模型进行政策情景仿真，分析不同政策情景下的京津冀人口数量、结构和分布的变动趋势。本文创新点在于建立了区域人口迁移复杂系统，用多主体建模的方法对人口迁移系统进行仿真，自下而上地模拟区域人口迁移行为，同时将传统的人口预测与多主体模型相结合，基于系统演化给出了未来人口的动态变化规律。本文对未来京津冀三地的人口的动态预测和人口老龄化的变动趋势分析，具有重要的政策指导价值，本文构建的人口迁移多主体模型也体现了系统的复杂性、随机性和稳健性。

本文的主要结果包括：（1）在不考虑人口迁移流动的情况下，以京津冀三地目前的人口规模和结构进行人口内生演化，未来人口总量都呈下降趋势；（2）在保持人口规模不变的前提下，只考虑迁移因素， 北京未来迁入效应持续上升且大于迁出效应，天津未来的迁入和迁出效应基本抵消，人口较为稳定，河北省在2030年后由于雄安新区的发展，迁入效应将占据主导地位；（3）基于人口内生演化和人口迁移的动态演化，北京和天津人口总量都在2021-2038年上升，至2038年左右达到峰值，而后人口数下降，河北省人口总量呈先降后升的趋势，在2035年为低谷；（4）未来京津冀三地的老龄化都愈加严重，但是老龄化程度不均衡。其中，北京人口老龄化程度最高，天津次之，河北最低且略高于全国平均水平；（5）雄安新区的设立和发展，会影响河北省迁入率和迁移人口的年龄结构，进一步影响三地人口数量，并在2040年后使河北省的老龄化程度降低。这些结论为我国政府和社会统筹规划，应对京津冀三地的人口老龄化提供了重要的决策依据，将极大提高京津冀高质量协同发展水平。

In 2014, the Central Committee of the Communist Party of China proposed the national strategy of coordinated development of the Beijing-Tianjin-Hebei region. In 2017, China officially established the national level Xiong'an New Area. After several years of practical exploration, Xiong'an New Area has achieved initial results in relieving non capital functions and promoting the formation of a new development pattern of "one core, two wings". However, there are still some shortcomings in the coordinated development of the Beijing-Tianjin-Hebei region, mainly rooted in the population problem in the region. The population size, age structure, and spatial layout are important endogenous variables that determine social and economic development, and are also key factors that constrain the coordinated development of the Beijing-Tianjin-Hebei region. In this context, scientifically predicting the changes in population size and structure in the Beijing-Tianjin-Hebei region from 2021 to 2050, analyzing the trends of population migration and aging, and understanding the spatiotemporal evolution characteristics of future population aging in the Beijing-Tianjin-Hebei region can promote the rational distribution of regional population space, improve the matching degree of resources and services to cope with population aging, and promote high-quality coordinated development of Beijing-Tianjin-Hebei integration.

The research work on the population of the Beijing-Tianjin-Hebei region in this article mainly includes three parts. Firstly, based on the queue element method, a population prediction model is established using the Leslie matrix, and based on the data from the seventh national census, the static population of the Beijing-Tianjin-Hebei region from 2021 to 2050 is predicted, that is, the endogenous evolution of the population; Secondly, a complex system of population migration in the Beijing-Tianjin- Hebei region was constructed, and an agent-based simulation model of regional population migration was established through agent-based modeling method. Simulate the migration process of population from bottom to top, and demonstrate the changes in population mobility and migration in the Beijing-Tianjin-Hebei region in the future; Thirdly, combining population endogenous evolution and population migration, analyze the future population size, structure, and aging trends in the Beijing-Tianjin-Hebei region, and consider the policy factors of Xiong'an New Area. Based on the agent-based model, conduct policy scenario simulation to analyze the changing trends of population quantity, structure, and distribution in the Beijing-Tianjin-Hebei region under different policy scenarios. The innovation of this article lies in establishing a complex system of regional population migration, simulating the population migration system using agent-based modeling methods from bottom to top, and combining traditional population prediction with agent-based models to provide dynamic changes in future population based on system evolution. This article has important policy guidance value in predicting the population dynamics and analyzing the trend of population aging in the future Beijing-Tianjin-Hebei region. The agent-based model of population migration constructed in this article also reflects the complexity, randomness, and robustness of the system.

The main results of this article include: (1) Without considering population migration and mobility, using the current population size and structure of the Beijing-Tianjin-Hebei region for endogenous population evolution, the total population in the future is showing a downward trend; (2) On the premise of maintaining the same population size and considering only migration factors, the future migration effect in Beijing will continue to rise and exceed the migration effect. The migration and outflow effects in Tianjin will basically cancel out, and the population will be relatively stable. After 2030, due to the development of Xiong'an New Area, the migration effect will dominate in Hebei Province; (3) Based on the dynamic evolution of population endogenous evolution and population migration, the total population of Beijing and Tianjin both increased from 2021 to 2038, reaching a peak around 2038, and then decreasing. The total population of Hebei Province showed a trend of first decreasing and then increasing, with a trough in 2035; (4) The aging population in the three regions of Beijing, Tianjin, and Hebei will become increasingly severe in the future, but the degree of aging will be uneven. Among them, Beijing has the highest degree of population aging, followed by Tianjin, and Hebei has the lowest and slightly higher than the national average; (5) The establishment and development of Xiong'an New Area will affect the immigration rate and age structure of the migrant population in Hebei Province, further affecting the population size of the three regions, and reducing the degree of aging in Hebei Province after 2040. These conclusions provide important decision-making basis for the coordinated planning of the Chinese government and society to address the aging population in the Beijing-Tianjin-Hebei region, and will greatly improve the level of high-quality coordinated development in the region.