Hydraulic oil cylinder capable of preventing internal leakage

The hydraulic oil cylinder comprises a base, a main cylinder and a hydraulic rod, the main cylinder is fixedly arranged at the top of the base, the hydraulic rod is embedded in the inner side of the main cylinder, the hydraulic rod comprises a piston and a hydraulic rod body, the piston is embedded in the inner side wall of the main cylinder in a sliding and sealing mode, and an upper sealing device and a lower sealing device are arranged on the periphery of the piston. A sealing rubber piece is annularly arranged on the outer edge of the sealing device. The piston at the bottom of the hydraulic rod is provided with the sealing device, the sealing device comprises the circular ring, the fan-shaped ejector blocks and the telescopic springs, the fan-shaped ejector blocks are embedded in the circular ring and abut against the sealing rubber part under certain pressure through the telescopic springs, and when the sealing rubber part is abraded, the corresponding fan-shaped ejector blocks eject outwards, so that t