There are multiple fluid-solid couplings in downstream docking process of hydraulic ship lift,such as the ship and the cabin,the cabin of the water and the ship,the shaft of water and the balance of weight.Therefore docking process ship crane force is more complicated than the traditional wire winding type ship lift.In order to ensure the safe and efficient docking operation of the hydraulic driven ship lift,we study the working condition and the downstream docking position of the hydraulic driven ship lift.By means of Jinghong hydraulic ship lift prototyping downstream docking process test,we discuss the influence of downstream brake operation and the docking position,deduce the formula of the displacement of the ship lift when the brake is not on,and obtain the applicable conditions of the brake working mode and the docking position.