The invention relates to a hydraulic car leg oil cylinder, and belongs to the technical field of hydraulic control systems. The problems that in the prior art, due to side force, the surface of a piston rod is mechanically damaged, and seal of a hydraulic car leg oil cylinder fails are solved. The hydraulic car leg oil cylinder comprises a piston rod, an oil cylinder arranged on the outer side of the piston rod in a sleeving manner, an inner sleeve and an outer sleeve arranged on the outer side of the inner sleeve in a sleeving manner; the oil cylinder is in sliding connection with the piston rod, the inner sleeve is in sliding connection with the outer sleeve, the oil cylinder is located in the inner sleeve, the top end of the outer sleeve is connected with the top end of the piston rod, the top end of the inner sleeve is connected with the top end of the oil cylinder, during use, the outer sleeve is fixedly connected with a car leg connecting beam, and the bottom end of the outer sleeve is in contact with the ground. The hydraulic car leg oil cylinder can be used for auxiliary supporting and leveling of a movable platform.