As the water quality of artificial lakes and other water sources in the newly built urban ecological park cannot meet the standards, it is necessary to build a water ecological self purification system in the park during the construction process. Therefore, taking the expansion project of Chengdu Panda Base as an example, the water environment barrier system in the lake area was built by analyzing the terrain data in the environment of the panda habitat. Through the terrain catchment analysis and catchment point simulation within the site, the pollution load of the lake was analyzed,the aquatic ecological environment of wild giant pandas was simulated, and a self- purification three-dimensional water ecosystem was built. The results show that TSS (total suspended solids), TN (total nitrate) and TP (total phosphorus) have been significantly reduced after the construction of the self purification three-dimensional water ecosystem, and the purification of the ecological park has gradually improved from surface Class III water body to Class I water body.