The stage of the Puyang River waterway is not only influenced by the runoff peak discharge in the upstream regions，but also supported by the tidal water in the downstream regions. Thus，the reasons for the high stage are complex. It is very urgent to demonstrate the navigable stage of the waterway for strengthening the management of navigation-related structures such as navigation channels and bridges and further enhancing the capacity of the waterway. In the Navigation Standard of Inland Waterway，the designed highest navigable stage is deduced by the design flow method with the stages in flood recurrence periods at different levels. In light of this，we establish a two-dimensional hydrodynamic mathematical model to calculate the designed highest navigable stage for 5-year，3-year and 2-year flood recurrence periods. Taking into account the river channel conditions，channel grades，flow conditions and bridge’s navigation clearance，we recommend the stage of Puyang River in the 2-year flood recurrence period as the highest designed navigable stage by referring to the data of designed stages upstream and downstream，characteristic stage under flood control and historical stage statistics.