The construction of water ecological security pattern can control the disorderly development of urban spatial interface and realize the sustainability of urban green development. The study quantitatively evaluates the value of supply side and demand side of ecosystem services through 6 factors: water conservation, high temperature regulation, carbon fixation and oxygen release, recreation and entertainment, food production and gas purification, and it is classified according to the difference between supply and demand and determines important ecological sources in combination with MSPA. The minimum cumulative resistance model is used to extract the primary and secondary ecological corridors, and the ecological security pattern of the main urban area of Chongqing is constructed. The results show that 17 important ecological sources in the main urban area of Chongqing are identified, with a total area of 148.1 km2, which are mainly distributed in the southeast mountains of Banan District and the North mountains of Yubei district. There are 48 extraction corridors in total, including 23 main corridors and 23 secondary corridors, 2 Liangjiang ecological corridors, and 17 ecological supply nodes and 7 demand nodes respectively. The main and secondary corridors form an ecological green network covering the whole main urban area of Chongqing. The ecological security pattern scheme constructed in this paper can provide a reference for the regional ecological security and regional ecological civilization construction in the main urban area of Chongqing, and provide a theoretical basis for the follow-up ecological security strategy construction of Chengdu Chongqing double city economic circle.