Abstract: The paper aims to explore the dynamic changes of land use performance and the mechanism of obstacle factors in Lanzhou. We took the entropy weight method and optimized TOPSIS method to evaluate the land use performance of Lanzhou with the evaluation index system from 4 levels (input level, utilization degree, benefit and ecological sustainability), then used the obstacle degree model and SPSS correlation test to judge the obstacle factors and analyzed the mechanism. The results show that: the land use performance of Lanzhou has increased year by year, and the performance value increased from 0.192 to 0.707 from 2006- 2015, achieving a transition from low performance to good performance; the obstacle degree of land use level and benefit have decreased year by year, while the obstacle degree of land input and ecological sustainability have increased year by year, in the long run, the degree of land use is still the primary factor affecting the overall performance of land use in Lanzhou. Therefore, it is suggest to raise the construction land area per capita, to control the population density rationally, to develop a three-dimensional model, to adjust the land use structure scientifically, and to optimize the overall resource.