The utility model discloses a sealing structure for a piston front end cover of a hydraulic oil cylinder. The oil cylinder comprises an oil cylinder barrel body, a piston, a piston front end cover, asealing ring and a fastening screw, the piston is assembled in the oil cylinder barrel body; an oil groove is formed in the outer diameter of an end cover sleeve of the piston front end cover, an O-shaped sealing ring is arranged in the oil groove, the piston front end cover is connected with the oil cylinder barrel through a fastening screw, the piston front end cover is composed of the end coversleeve and an end cover face, a groove is formed in the outer diameter of the end cover sleeve at the joint of the end cover sleeve and the end cover face, and a sealing ring is arranged in the groove. And a second sealing protection measure is implemented, so that the problem of oil leakage of the joint surface of the front end cover and the oil cylinder barrel is thoroughly solved. The stability of oil pressure is guaranteed, the hydraulic oil cylinder can stably operate for a long time, and meanwhile, as oil does not leak any more, the surface of equipment is clean, the field ground is clean, and the working environment is greatly improved. In addition, the device is simple in structure and easy to process, and the cost can be saved.