When the ship lock is connected to the navigation tunnel and directly draws water from the tunnel,a significant unsteady current will be generated in the tunnel,which will greatly affect the safe navigation of ships.In view of this arrangement,we propose a concept of ship lock tunnel type of approach channel.Relying on the newly built ship lock project of the Baishi hydropower station in Qingshuijiang,Guizhou,we use a 136 normal overall hydraulic model and a combination of remote-controlled self-sailing ship models to study the navigation flow conditions and ship navigation parameters of the tunnel type of approach channel of various cross-section scales when the ship lock is filled and emptied with water，and propose the safe and economical cross-sectional dimensions of the navigation tunnel and the ship navigation parameters in the tunnel.The results show that the safety of ship navigation in the tunnel is determined by a flow velocity of no more than 0.5 m/s,a water level fluct of no more than 0.5 m,and a rudder angle of no more than 25°.The recommended clear width of the Baishi ship lock navigation tunnel is 22 m.