In view of the frequent occurrence and serious loss of urban waterlogging disasters in recent years, this paper focuses on the current situation of engineering of waterlogging drainage, and takes Lu'an City, Anhui Province, which experienced waterlogging disasters in 2016 and 2020 as the research object. Considering the connection relationship between drainage network and drainage channel systematically, the study analyzes and determines the engineering weakness that cause urban waterlogging from the aspects of the standard of drainage network corresponding to the location of water logging points, the relationship between ground elevation and the design water level of the corresponding receiving rainwater river, the drainage capacity of the river, and the operation conditions of the drainage pumping station, based on the tracking of rainwater discharge process of pipe network-inland river-outland river. The results show that the elevation of water logging point in the old urban area of Lu'an City has the condition of flowing into the river by gravity, and the drainage channel and drainage pumping station can meet the drainage requirements. The main engineering reason for the occurrence of waterlogging is that most drainage network have low standards and can not drain rainwater into the river in time. On this basis, it is further considered that the implementation of the drainage network rectification in the old urban area is difficult and long cycle. In order to minimize the risk of waterlogging before rectification, it is proposed to reduce the operation water level of the drainage pumping station at the estuary of the outland river, so as to improve the ability of urban drainage and disaster reduction.