Hydraulic ship lift brakes use normally closed brake.In the normal docking process of the ship,and the condition of cabin leveling and accident,the brake has the effect of retaining the position of the box,preventing the balance side and the ship chamber side rope force transmission and protecting the synchronous axis.Due to the breaking of the load real-time balance system between balance weight and ship chamber after the ship lift hydraulic brakes,the corresponding loose conditions must be met before the release of brake,otherwise the safe operation condition of the ship lift is been damaged.Based on Jinghong hydraulic ship lift,the brake application condition and the judgment of loose condition are systematically analyzed.The judging basis of the brake condition and the release condition of the hydraulic lifter is obtained.