The Aircraft hydraulic power system provides hydraulic energy for aircraft. When the aircraft hydraulic system provides large flow to the hydraulic users, the suction pressure of the engine driven pump will be sharply reduced, and the pump inlet pipeline is prone to cavitation. Base on the problem of low pump suction pressure in aircraft hydraulic system, the main factors affecting the suction pressure are studied through theoretical analysis and simulation analysis. The AMESim simulation analysis and calculation can explore the factors that affect the suction pressure of the pump, such as the accumulator, pipe diameter and reservoir pressure, and then the cavitation phenomenon can be avoided as much as possible through reasonable parameter setting.