The flow patterns in the intersection area of tributary and main stream are complicated,and the artificial canal excavation has the characteristics of large intersection angle and large inlet flow,which has a significant impact on channel navigation,so it is necessary to implement the river treatment projects at the tributary mouth.Aiming at the navigation problem of the main stream of Pinglu Canal after the tributaries of Niujiang River and Xiadi River merge into the canal,this paper studies the flow movement characteristics of the incoming reaches.Based on the RNG k-ε turbulence model,a three-dimensional numerical simulation method is used to simulate the branch inflow conditions under different design conditions.The results show that the original design scheme does not meet the navigation conditions.Therefore,optimization measures such as reorientation of the inflow and expansion of the inflow section are proposed on the basis of the design scheme,which significantly improves the navigable water flow conditions and meets the requirements of the code.The research results can provide reference for similar projects.