The reclamation area utilization rate has been improved significantly in recent years. In order to ensure the safe use of the area, the paper analyzed the influence of scale and operation of drainage pump station group on drainage system. Through setting up a numerical simulation model of flood control and drainage within port-centered industry zone in Tianjin,it analyzed the drainage capacity of water system and the possible of flood disaster, gave the scale of drainage pump station and got the relationship between flows of rainfall pump station and drainage pump station, the relationship between scale and submersion time of drainage pump station. The method and think provide the reference basis for the design and construction of similar drainage pump station.