The embodiment of the invention relates to the technical field of air distribution for engines, and discloses a device for realizing controllable return strokes of air intake valves of an engine. The device comprises an electromagnetic valve, a pull rod, an oil chamber and a piston, wherein the pull rod is connected with the electromagnetic valve; an oil inlet hole and an oil outlet hole are arranged in the upper end of the oil chamber respectively; the pull rod is controlled to move back and forth along the axial direction of the pull rod by the electromagnetic valve, so as to drive the pull rod to seal or open the oil outlet hole; the piston is in matching connection with the oil chamber; and one end of the piston is located in the oil chamber, and the other end of the piston is located outside the oil chamber. The embodiment of the invention further discloses an air distribution system for an engine. According to the device and the air distribution system which are disclosed by the embodiment of the invention, an air intake amount of the engine can be controlled, thus combustion is optimized, and then the performance of the engine is improved.