Sealing device of hydraulic oil cylinder and hydraulic oil cylinder

The invention provides a sealing device of a hydraulic oil cylinder and the hydraulic oil cylinder, and belongs to the technical field of underwater operation. The hydraulic oil cylinder comprises a piston rod and a cylinder body which are sequentially arranged in water in the vertical direction from top to bottom. The sealing device comprises an isolation hood filled with gas, gas supplementing equipment, a first pressure sensor and a second pressure sensor, the isolation hood is arranged outside the hydraulic oil cylinder in a sleeving mode, the upper end of the isolation hood is fixed outside the piston rod in a sealed mode, the lower end of the isolation hood is located outside the cylinder body, the gas supplementing equipment communicates with the interior of the isolation hood, thefirst pressure sensor is arranged on the inner wall of the isolation hood, the second pressure sensor is arranged on the outer wall of the isolation hood, and the first pressure sensor and the secondpressure sensor are corres