During the upgrading and reconstruction of the rainwater system in Zhangjiabang,Lujiazui,Shanghai,due to the elevation limit of the current rail transit,the rainwater main pipe cannot be implemented according to the planned pipe diameter,resulting in ponding on the ground in local low-lying areas.InfoWorks software is used to simulate the working conditions in the pipe network system,set the peak shaving storage tank,and increase the connecting pipe to connect with the adjacent rainwater system,and analyze and demonstrate the water inlet,outlet and operation mode of the storage tank.The results show that when the waterlogging point produces water,opening the storage tank can make the storage tank play the maximum effect.The combination of gravity flow and pressure flow is adopted to speed up the emptying,improve the efficiency of the storage tank and save energy consumption.A fully automatic control operation mode of the storage tank is proposed.