According to the principle of excavator hydraulic system and the functions of each component, the hydraulic system can be divided into power module, execution module, control module and auxiliary module. Figure 1 is the hydraulic schematic diagram of a modern brand excavator, in which the main pump 1 is the power module, and the swing motor 3, the walking motor 4, the left boom cylinder 8, the right boom cylinder 9, the stick cylinder 10 and the bucket cylinder 1 1 are the execution modules, and the main control valves 2 and 2 are the main control valves.