Abstract: There is a complex coupling relationship between urbanization and ecological environment. It is an effective mean to clarify the coordinated development mechanism of "social economic development, land use, ecological environment" by studying the ecological environmental effects of urban expansion. Based on the land use data from 2011 to 2015, using “P-S-R” model evaluation index system and the coupling coordination model and its classification principle, this paper comprehensively analyzes the spatial and temporal differentiation characteristics of the ecological environment effect of urban expansion in Chongqing city, and reveals the coordinated development pattern between the urbanization and urban ecological environment. The results showed that: (1) The socio-economic pressure and land status index of urban expansion in Chongqing city were generally low, and the ecological environment response index remained at a medium level. (2) The comprehensive eco-environmental effects of urban expansion in Chongqing city was generally at a relatively low level. During the study period, the overall comprehensive effect index decreased slightly, and the overall and local variation ranges were no more than 10%, and the spatial difference was not significant. The main reason lied in the benefit superposition, mutual restriction and mutual promotion among the socio-economic pressure, land use status and ecological environment response. (3) The coupling degree and coupling coordination degree of "socio-economic, land, ecology" in the whole city declined in volatility. The average coordination degree was between 0.543 and 0.581, which was in the stage of barely coordination. (4) The nine districts in downtown and Fuling, Wanzhou, Yongchuan were in the economy leading model, and the serious lag of land use was the main factor restricting the coordinated development of the main urban system. Except Chengkou County, 25 districts and counties belong to the ecology leading model, in which the serious lag of economic development level in southeast and northeast Chongqing was an important factor leading the imbalance of the system. The backward socio-economic development and land-use in the east and west of the main city were the important reasons restricting its coordinated development.