The invention provides an active heave compensation device for releasing and assembling a deep sea winch. The device comprises a movable pulley, a movable pulley mounting bracket, a piston rod, a hydraulic cylinder, a fixed pulley mounting bracket and a fixed pulley, wherein a piston is arranged on the piston rod, and is embedded in a hydraulic cylinder body, so that the piston and the inner wall of the hydraulic cylinder body are sealed through hydraulic oil to form a hydraulic execution mechanism; the movable pulley is arranged on the movable pulley mounting bracket, and the movable pulley mounting bracket is connected with one end, away from the piston, of the piston rod; and the fixed pulley is arranged on the fixed pulley mounting bracket, and the fixed pulley mounting bracket is connected with the bottom of the hydraulic cylinder. By utilizing the device, the up-and-down movement of underwater equipment caused by the fact that a vessel body moves up and down along with waves in a deep sea releasing and assembling process can be compensated, the constant tension of ropes connected with underwater production facilities can be maintained, and the stability and safety of releasing and assembly can be ensured.