In order to explore the impact of river level and total rainfall duration on the drainage performance of rainwater pipe network, an integrated SWMM generalized model of pipe network and river in a certain industrial park was constructed. Based on the rainfall events with a return period of 5 years and the total rainfall duration of 2 h and 24 h, the drainage conditions of rainwater pipe network and river in industrial parks with different initial river levels were simulated and analyzed. The results show that when the initial river level is low and the outlet is free outflow, river level has little impact on the drainage performance of the rainwater pipe network. When the outlet is submerged, with the increase of the initial river level, the proportion of overloaded pipelines and overflow nodes in the drainage system increases, the overload time and overflow time are prolonged, the peak flow of outlets and pipeline nodes decreases, and the peak flow of node which is closer to outlet decreases more sharply. Based on the same rainfall return period and the initial river level, compared with the short duration rainfall, the proportion of overloaded pipelines and overflow nodes in the long-duration rainfall is larger, the overload time and overflow time are longer, and the peak flow of outlets and pipeline nodes decreases greatly. When designing the storm water drainage system with river-pipe network, it is advisable to check the drainage performance of storm water drainage system for 24 h rainfall and different river levels.