With the rapid development of shipping industry,the multi-line ship lock is expanded in China,which is restricted by the established structure and the landform.Considering the management problem,the new multi-line ship lock is mostly arranged with the established ship lock side-by-side to share the approach channel.While,the filling or drain of a line ship lock would affect the flow condition of the other lock approach channel,which may affect the ship safety and the structure of ship lock at another line.Based on the hydraulic model study of Feilaixia ship lock at the Beijiang River,we carry out the investigation on the effect of navigation flow with sharing the approach channel of ship lock at same level.The results show that the flow can diffuse rapidly with increasing the diffusion angle of the intermediate counseling wall,and the range and strength of reflux decrease.The approach channel flow condition of multi-line ship lock with sharing the approach channel can be improved by optimizing the counseling wall and the energy dissipative shape.