Abstract: In order to study the pressure impact characteristics of the hydraulic lifting system with auxiliary cylinder in a Dongfanghong tractor, taking the hydraulic lifting system and hitch mechanism as the research objects, the physical and mathematical models of the system during the lifting and dropping of farm tool are established. The simulation model of hydraulic system is established by AMESim software. The validity of the model is verified by testing the tractor prototype. The results show that the pressure impact of the three groups of oil cylinders without rod cavity is only 4.72 MPa when the farm tool is lifted, and the pressure in the whole lifting process is stable; when the farm tool is dropped, the pressure impact of the strong pressure oil cylinder is large, the pressure in the rod cavity suddenly increases to 23 MPa. If the farm tool suddenly lands on the ground, the pressure impact produced by the rod cavity of the strong pressure cylinder is directly proportional to the weight of the farm tool. Proper back pressure in the oil return pipeline can effectively prevent the tool from falling too fast. This method has guiding significance for studying the performance of the hydraulic lifting system with auxiliary cylinders and provides a way of thinking for further optimization design.