Abstract: The construction of ecological security pattern is an important way to ensure the stable operation of ecosystem and realize regional ecological security. This article takes Chongqing as an example, evaluates the ecological importance of Chongqing based on its ecological service functions and ecological sensitivity, and takes high-level areas of ecological importance and nature reserves as the ecological source. Six resistance factors, including elevation, slope, land use type,distance from road,distance from waterbodyand night light index, are selected from the ecological background and ecological stress to construct the ecological resistance surface of typical mountain animals, and the minimum cumulative resistance model (MCR) is used to simulate the potential ecological corridors, and then the urban ecological security pattern is constructed. The research shows that the ecological source area of Chongqing is 30 751.11 km², accounting for 37.32% of the total area of Chongqing, which is mainly distributed in the mountain forest land in the northeast and southeast of Chongqing. The identified 73 potential ecological corridors and 138 ecological nodes are superposed with ecological sources, and combining with the landscape pattern of Chongqing, a multi-level ecological security pattern of "two regions, three belts, four cores, multiple corridors and multiple points" was constructed, which provided scientific reference for ecological protection and restoration work in Chongqing.

Key words: ecological security pattern, minimum cumulative resistance model, ecological service function, ecological sensitivity, Chongqing city