The large miter gate of ship lock is characterized by large plane scale，high water retaining head and large submergence depth. Its performance and operation safety are closely related to the hydrodynamic characteristics. The hydrodynamic characteristics of large miter gate are studied comprehensively through mathematical model and physical model. Based on the analysis of the influence of gate library boundary conditions on the peak value of hydrodynamic resisting torque of miter gate，we put forward the scientific and reasonable shape of large miter gate library，and determine the gap at the bottom of the gate，the depth of the gate library and the connection mode between the gate library and the upstream and downstream side walls. Based on the physical model of 1:20 miter gate，we study the characteristics of opening and closing force and hydrodynamic resisting torque of miter gate under uniform and variable speed operation，analyze the change rules of miter gate position and angular velocity under different opening and closing modes，and propose the variable speed operation mode of miter gate of Datengxia shiplock. The experimental results show that the variable speed operation mode can significantly reduce the maximum opening and closing force of the miter gate and reduce the difficulty of the operating machinery design. By studying the characteristic indices of the inertia water head and reverse surge under different operation conditions of lock and hydro-junction and the characteristics of miter gate drift under the action of the reverse surge，we put forward comprehensive measures to deal with the drift of large miter gate.