Baoying junction is located at the end of the connecting section of the S-shaped bend in the upper reaches of the main stream of the Baihe River.The river section has the characteristics of small flow in non rainy season and sharp rise in rainstorm season.The upstream approach channel of the ship lock is affected by the topographic conditions of the bend and the river section,and the flow conditions in the entrance area are very disordered,which is difficult to meet the navigation requirements.In view of the complex flow regime in the upstream entrance area of the ship lock,combined with the characteristics of the dam site and the navigation requirements of the ship lock,this study conducts a numerical simulation of the overall flow conditions in the upstream channel of the junction.By analyzing the causes of the adverse flow conditions,this study proposes the treatment measures of “horn” inlet+permeable breakwater and carries out comparison and optimization.The results show that adjusting the shoreline shape and adding a suitable permeable breakwater project can significantly improve the complex flow regime in the entrance area and ensure the navigation safety of ships passing through the ship lock.The research results can provide technical reference for similar projects.