The hydraulic system design of the double-sided milling machine can be opened in dwg form, cad and caxa. For the design of the hydraulic system, the purpose and requirements of the design must be clarified first, the required data must be collected, and then the working condition analysis, analysis of working load, friction resistance, drawing of load diagram, etc. Secondly, analyze the oil circuit, draw the system diagram, select the hydraulic components, and calculate the hydraulic cylinder