在中国城镇化飞速发展的背景下，城市建设用地的需求不断增加，城市土地利用也发生了巨大的变化，协调城市建设用地、农业以及生态用地之间的矛盾是实现高质量发展的关键。而青藏高原地区由于其脆弱的生态环境，如何协调该地区城市发展与生态保护的矛盾就显得更加重要。本文以青藏高原地区典型城市格尔木市为例，旨在研究2000 - 2020年间格尔木市的城市扩张时空演变特征，并利用FLUS模型对格尔木市2030年及2050年在自然发展情景、耕地保护情景以及生态保护情景下的城市扩张进行多情景模拟预测^[1]，分析格尔木市在不同情景下的土地利用特征及时空变化格局，以期为青藏高原地区生态保护及城市发展提供参考借鉴。

基于2000年、2010年和2020年三期土地利用数据以及格尔木市自然、人文驱动因素相关数据，本文利用QGIS软件，结合土地利用转移矩阵以及标准差椭圆的空间分析方法，对格尔木城市20年来城市扩张的时空演变特征及时空演化格局进行了分析；同时利用GeoSOS-FLUS软件，运用FLUS模型对格尔木市2030年及2050年三种不同土地利用情景进行了预测模拟，综合分析得出以下结论：

（1）格尔木市城市扩张的时间变化方面，2000-2020年间城市面积整体增长，建设用地不断增加但增速不大，生态建设用地波动变化，未利用土地开发潜力较大且较多转化为建设用地，城市扩张对生态用地和耕地的侵占较大。

（2）在土地利用空间变化特征方面，格尔木市2000-2020年间的土地利用变化主要表现为其他各类土地利用类型不同程度地转化为河流、湖泊等水体及城市建设用地，其中未利用地转出面积最大，耕地和草地面积波动变化；其次通过标准差椭圆分析得出格尔木市重心先向西北后向西南部转移，主要原因为国家政策规划以及西部大开发战略下格尔木市建设用地的扩张。

（3）格尔木市未来扩张预测方面，在模拟精度较高的前提下预测得到格尔木市2030年及2050年在3种不同情景下的土地利用格局。在自然发展情景之下，格尔木市的城市建设用地规模会继续增长，但增长速度不快，对生态用地侵占严重。在生态保护情景下，建设用地扩张整体受到制约，耕地面积保持相对稳定，林地、草地以及水域面积将会保持增长。在耕地保护情景下，耕地资源得到重点保护，耕地面积在短期内保持相对稳定，但长期内只有略微增加，增长数量及比例均不大，推测主要原因为受到当地自然地理条件的限制。

Against the backdrop of China's rapid urbanization, the demand for urban construction land has been increasing and urban land use has undergone tremendous changes. Harmonizing the conflicts between urban construction land, agricultural land, and other types of land is the key to achieving high-quality development. In the Tibetan Plateau region, due to its fragile ecological environment, how to carry out land use planning in an orderly and rational way needs to be solved urgently. This paper takes Golmud City, a typical city in the Tibetan Plateau region，expansion and its spatial distribution pattern in Golmud City during the period of 2000 - 2020, and utilizes the FLUS model and combines the influencing factors of nature, society, and economy to predict the urban expansion of Golmud City in the year of 2030 and 2050 in the different scenarios. A multi-scenario simulation was conducted to analyze the land use characteristics and spatial and temporal changes of Golmud City under different scenarios, with a view to providing references for the promotion of scientific and rational expansion of urban space and ecological protection in the Tibetan Plateau region.

Based on the three-period LUCC land use data in 2000, 2010 and 2020, as well as the data related to the natural and humanistic driving factors in Golmud City, this paper analyzes the spatial and temporal characteristics over the past 20 years by using the QGIS software, combined with standard deviation ellipse. GeoSOS-FLUS software, the FLUS model was used to predict and simulate the comprehensive land use pattern of Golmud City in 2030 and 2050 under three different land use scenarios, and the comprehensive analysis led to the following conclusions:

(1) In terms of the temporal change of urban expansion in Golmud City, the overall urban land area shows a growing trend during 2000-2020, the unutilized land development potential is larger, the development of the city is slower in the early stage , and land use is further strengthened, and at the same time, the city occupies part of the arable land, forest land, grassland, and watersheds in the process of construction.

(2) The area of arable land and grassland fluctuates and changes; and secondly, through the standard deviation ellipse analysis, it is concluded that the center of gravity of Golmud City is firstly transferred to the north-west and then to the south-west, which is mainly The main reason is the expansion of construction land in Golmud City under the national policy planning and western development strategy.

(3) As for the prediction of the future expansion of Golmud City, the land use pattern of Golmud City in 2030 under three different scenarios is predicted on the premise that the simulation accuracy is more than 81%, and the accuracy is high and feasible.In Golmud City will continue to grow, but not at a fast rate, focusing on the further utilization of existing construction land, mainly in the eastern part of the city; under the ecological protection scenario, the expansion of construction land will be constrained by the limitations of protecting ecological land, and the stability of cropland, woodland and grassland will be strengthened to varying degrees, resulting in the conversion of woodland, which will increase the amount of forested land.