The high waterbased and high pressure large flow safety valve is one of the key components of hydraulic support system. Its sealing performance directly affects the working performance of hydraulic support. Specific tothe high pressure and large flow rate differential type safety valve and based on ADINA, the sealing material characteristics and the necessity of the selection of combined sealingwere analyzed. Moreover,under high pressure and large flow conditions,the suitable precompression of this safety valve combined sealing components was determined. It provides technical supports for leakage controlling to safety valve.