Abstract: Multi-valve pump can operate normally so long as either of the travel1ing va1ve seat and the static va1ve seat doesn' t leak. However, the use of multi-valve increases system resistance, resu1ting in fluid energy loss and pressure hysteresis of the travelling va1ve which are unfav0rable for raising pump efficiency. On base of ca1culation of partia1 energy loss and analysis of pressure hystercsis, it is believed that energy loss caused by multi- valve is very small and can be neglected.