A power winch horizontal-pull clutch device provides dynamic forces from a power source and uses a deceleration device to retard the force transmission to a cable pulley for releasing and rewinding a steel cable on the cable pulley. A connecting slot is formed on a casing of the deceleration device. The deceleration device includes an outer ring body and at least one insert slot formed on an external surface. The power winch includes a clutch device for selectively fixing the connecting slot to the insert slot to transmit the dynamic force from the deceleration device to the cable pulley. The clutch device is a sealed assembly and a control handle is provided for making a horizontal movement to achieve the clutching effect and prevent water, dust or other foreign matters from entering into the clutch device, damaging components, causing failure or malfunction, or clamping an operator's hand or foreign matters.