In order to meet the high power density requirements of aviation pumps,valve flow distribution is adopted to effectively reduce leakage and improve volume efficiency of micro high pressure piston pump.Aiming at the main factors affecting the flow output characteristics of micro high pressure piston pump,the mathematical model of micro high pressure piston pump with valve distribution was established,and flow distribution models of check valves with different structures were built by AMESim.The modeling and simulation experiments of ball valve,cone valve,plate valve and other check spool valve forms with different combination structures were carried out.The influence factors such as micro-pump clearance volume,swash plate angle,load pressure,check valve spring stiffness and spool mass were simulated and analyzed.The results show that the valve combination form is the best when the inlet valve and the discharge valve are both plate valves under the existing structure;the micro-pump volume efficiency is stable under variable speed condition,and the spool mass has little influence on the distribution valve hysteresis;increasing the swash plate angle or decreasing the load pressure and the clearance volume can effectively improve the valve opening lag angle,and then improve the volume efficiency.