The invention discloses a full-automatic sealed hydraulic oil sampling device, comprising a machine body driven by a wheel, wherein a sample bottle storage box is arranged on the machine body for placing a sample bottle and a sampler, three mechanical arms are further arranged on the machine body, wherein a screw capping claw module is arranged at the end part of one mechanical arm, gripping modules are arranged at the end parts of the other two mechanical arms, a camera is arranged on the machine body for taking an environment image, and an ultrasonic obstacle avoidance module is further provided for avoiding obstacles. The full-automatic sealed hydraulic oil sampling device can realize full-automatic sealing to perform a hydraulic oil sampling work, the collected sample is less polluted,and the detection result is accurate and reliable; and meanwhile full-automatic sampling with a long distance and multiple sampling points can be performed on natural water bodies.