Aiming at the check performance of axial flow check valve,the effects of piston diameter,piston stroke and damping hole diameter of buffer structure on disc check performance were studied by using dynamic grid numerical test method,orthogonal test design and range analysis.The weight influence of the three structure parameters on check performance was analyzed,and then with disc closing time and the maximum liquid power in the check process as a target for multi-objective optimization design,the disc closing time was reduced under the condition of transient fluid power as small as possible to realize the “fast closing slowly-closing” and improve the stability of the valve.The results show that:at 0.035 2 s,the buffering damping of the flute buffer structure changes due to the change of through hole area,which causes the vibration of valve disc during the closing process.The improved buffering structure has constant damping,which improves the stability of the valve disc motion.Through range analysis of the three structural parameters orthogonal test results,it can be seen that the order of influence degree of the three structural parameters on disc closing time is:piston diameter (0.021 8)＞buffer stroke (0.017 8)＞damping hole diameter (0.013 5);the order of the influence degree on the maximum liquid force is:buffer stroke (204 107)＞piston diameter (140 362)＞damping hole diameter (140 086). Shortening the check time of the valve and reducing the vibration of the spool are two contradictory goals,there is no unique optimal structural parameter,and appropriate optimization results should be selected according to the actual working conditions.