The service life of hydraulic components,as well as the use performance,is affected by multiple factors,one of the important influencing factors is the annular gap.Now the electro-hydraulic proportional directional valve applying Valvistor valve control principle was taken as the research object.From its structure and working principle,several possible leakage paths were analyzed,and the mathematical model of the whole valve was established by using annular gap flow formula,disc gap flow formula and valve port flow formula.Based on this,a multidisciplinary simulation model of the proportional directional valve was established in SimulationX.The simulation analysis of the factors affecting the gap flow:gap width,gap length and gap end differential pressure on the performance of the proportional valve was done separately,and the simulation results matched with the theoretical results.The results show that the gap flow is mainly influenced by the gap width,and has good control performance on the spool displacement and output flow,especially on the pressure gain of the valve,which makes a good control sensitivity to the load pressure.