For the hydraulic problems of enlarged culvert at back of culvert valve of ship lock valve,based on Yinpan ship lock,emptying valve physical model with scale ratio of 1:10 is built,and the upward ramp type of enlarged culvert is optimized.Through unsteady flow test,hydrodynamic pressure characteristics of 6 types of enlarged culvert’s upward ramp are studied comparatively,then influence of upward ramp type on hydrodynamic load on enlarged culvert is discussed,and the optimum shape of upward ramp is recommend.All the above research conclusions can be used to guide the design and construction of enlarged culvert of high water head ship lock and can provide theoretical foundation and technical support for it.