To the problem of navigation obstruction in the Taoyuan hub ship lock,this paper takes the construction project of the Taoyuan hub second line ship lock in Yuanshui as the project basis,and uses two-dimensional dynamic numerical simulation method to study the navigable water flow conditions of the river section from Taoyuan Hub to Zhouwenmiao Hydrological Station.Based on the analysis of parameters such as water depth,water level and flow velocity under multiple working conditions,the navigable flow conditions and obstructed beach sections of the hub and downstream waterway are studied,and the channel improvement measures such as trench dredging are proposed according to the beach risk problem.The results show that under the existing terrain conditions,the navigation obstruction problems of working conditions 1 (Q=217 m3/s) and 2 (Q=380 m3/s) are prominent in the river section 0-20 km and 80-95 km from Taoyuan hub,and when the flow rate is greater than working condition 3 (1 233 m3/s),it meets the requirements of Class III channel scale.Through mathematical model verification,measures such as trench dredging can effectively improve the navigable water flow conditions of the waterway.