123 mL/min。A new type of piezoelectric pump with active valve was designed. By means of derivation piezoelectric pump flux formula, main factors which influenced flux of the active valve were analyzed, i.e. inside diameter and the width of the valve seat. The test result showed that working frequency, the power supply voltage, the output backpressure, phase difference between the driving signal of active valve and the pump were the most influential factors on the performance of piezoelectric pump with the active valve. The designed initiative piezoelectric pump has the capacity of delivering liquid in two directions. The experimental results showed that the flux of designed piezoelectric pump could reach 123mL/min, under the condition of sinusoidal driving signal at 30 Hz and 120 V.