In order to solve urban waterlogging problems effectively, it is necessary to study further about the reasonable relationship of the pipe drainage and river drainage. The damage rate method and the coherence method are usually used in the study of the relationship between the pipes drainage and river drainage nowadays. Choosing Suqian city of Jiangsu Province as study area, we apply these two methods in the study area to discuss the relationship between the pipes drainage and river drainage considering the influence of river water level and the balance of rainfall intensity. Results made by these two methods are generally similar, but when the standard of the pipes drainage is two years which is a low recurrence period, there occurs certain deviation. This research recommends that these two methods could be references for each other in practical application and offers a scientific guidance to the further construction and improvement of the drainage and waterlogging system.