Electric elevators are generally pulled up or down by winches; The hydraulic lift open that channel leading to the hydraulic cylinder and close the liquid return channel through the hydraulic oil of the hydraulic pump and the electromagnetic valve, and the hydraulic oil drives the plunger in the hydraulic cylinder to eject and rise; When descending, the solenoid valve closes the passage leading to the hydraulic cylinder and opens the liquid return passage, so that the oil in the hydraulic cylinder returns to the oil tank and the plunger retracts.