Abstract: The landscape fragmentation in urbanization has attracted considerable concern in recent years. Landscape fragmentation index as a quantitatively measurement for the reasonability of urban development has been widely used in researches. This paper selected four kinds of representative landscape fragmentation index in Yubei district of Chongqing, then analyzed the spatial pattern and internal differences of landscape fragmentation, and researched the relationships between landscape fragmentation and urbanization and the socialeconomic development level by the moving window method, gradient method, correlation and regression analysis. Results show that urban and forest landscape fragmentation of Yubei district is significantly lower than that in other lower altitude township units, the farther the city is away from the city center, the higher degree of the landscape fragmentation it has, and the numeric value begins to decrease when it comes to the top at the edge of the city. Population density is the direct affecting factor of the degree of landscape fragmentation, while the economic development is the indirect one. This research could contribute to reveal the internal spatial pattern of the evolution characteristics in southwest mountainous area, and also provide the theory basis for the biodiversity conservation, the green corridor maintaining and the construction of ecological civilization city.〖HJ1〗〖HJ〗〖HQ〗