The hydraulic system is suitable for all kinds of wheel grippers of cranes, cranes, dumpers, bucket wheel stacker reclaimers and other hydraulic stations with similar working conditions. At present, most crane trucks use wheeled grab when loading and unloading goods to prevent the truck from shifting due to excessive wind. Wheeled gripper needs hydraulic drive, and it needs a hydraulic system that can achieve the required working conditions effectively, quickly, with high requirements and low cost.