The existing hydraulic intensifier is a one-time booster structure. In addition, increasing the diameter of the cylinder to the booster much flow even longer stroke, inconvenient to mount and prices were rising rapidly restrictions for use. The present invention have solved the problems of the conventional hydraulic booster cylinder, a hydraulic booster cylinder formed a master valve and the pneumatic control circuit. Conventional booster cylinder is operated only once, but the present invention is operated repeatedly by a booster piston attached to the built-in booster pump. Therefore, even a small size with a hydraulic booster cylinder extend stroke of the hydraulic booster cylinder to maximize economic efficiency and usability.