Abstract:In order to explore the effect of low-impact development system (LID) on rain and flood control in red hilly area in southwest China, this article took wetland park demonstration area of hedong new area, suining city, China as the research object. To evaluate the flood control and waterlogging reduction effect of sponge city construction, the storm flood management model (SWMM) was built and the surface runoff process and infiltration process of low impact development (LID) measures under different rainfall recurrence periods (2, 5, 10, 20 years) were simulated according to the construction plan of sponge city and the characteristics of the underlying surface of the study area. The results show that LID measures can control 78% and 45% of surface runoff flood in the case of low rainfall recurrence period (1 in 2 years and 1 in 5 years), However the delay phenomenon of flood peak was not obvious. In the case of high recurrence period (1 in 20 years and 1 in 50 years), the surface runoff control rate was only 2% and 1%, the delay time of flood peak is up to 2h and 2.5h. It is concluded that LID measures have a certain effect on urban rain flood control. As the recurrence period of rainfall increased, the control effect of LID measures on urban rain flood weakens. This study provides a theoretical basis for the construction and later operation of sponge cities in southwest China.