Weishan three-line ship lock is the largest ship lock on the Beijing-Hangzhou Canal with an effective scale of 280 m×34 m×5.5 m (length×width×threshold depth) and a designed maximum water head of 4.0m.It is determined that the ship lock is adopt the form of end filling and emptying system according to the general layout of the ship lock and requirements of the code.On the basis of Weishan three-line ship lock project,a physical model test with geometric scale of 1:30 is established to study the hydraulic characteristics of the filling and emptying system.There are some bad hydraulic phenomena in the original scheme,such as the local formation of the funnel vortex,the uneven distribution of the flow velocity in the sluice chamber and the visible suction vortex in the intake of the drainage gallery.Some optimization measures are proposed to solve above problems,such as adding a permeable vortex eliminator at the water inlet,optimizing the arrangement of energy dissipation grid and adjusting the buried depth of drainage gallery.The results show that after optimizing the layout of the filling and emptying system,all hydraulic characteristics meet requirements of the code.