The invention discloses a marine piston-free engine and a drive method thereof. The engine comprises an engine body, the engine body comprises a shell, the shell comprises a water inlet, a water draining opening, an air exhaust opening, an air inlet opening, a cover A, a cover B and a cover C, a rotating shaft is arranged in the shell, a rotating wheel is arranged on the rotating shaft, a cylinderbody A, a cylinder body B, a cylinder body C and a cylinder body D are formed on the rotating wheel, oil spraying holes are formed in the side walls of the sides, close to the center of the rotatingwheel, of the cylinder bodies, the outer portion of the oil inlet opening is connected with an air supply device, the outer portion of the water inlet opening is connected with a water supply device,and the outer portion of the water draining opening is connected with a water draining device. Water is used for compressing gas in the cylinder bodies, the phenomenon that a traditional piston uses apiston to compress the gas in the cylinder bodies is replaced, through the method, multiple elements like a piston and a piston rod are omitted from the engine, and the engine has the important breaking significance in the existing technology.