The invention relates to a fuel-free device for operating and applying work by using circulating liquid or circulating gas. The device mainly comprises a universal joint (1), a crankshaft (2), a pushrod (3), an oil cylinder sealing ring (4), a cylinder body (5), an oil-pressure pump (6), an oil-pressure body (7), a battery power supply (8), a starter (9), a piston (10), hydraulic oil (11) and a circulating pipe (12). The device comprises the principle that the piston of the oil-pressure cylinder body is pushed to move up and down by oil pressure generated by the oil-pressure pump so as to drive the crankshaft to apply work; oil-pressure liquid can move circularly, and the power source of the oil-pressure liquid takes the battery power supply as power so as to enable a pressure pump to apply the work and enable a hydraulic pump to operate mechanically and generate motion force.