Abstract: In order to make the valveless piezoelectric pump with Y-shape tubes meet well with the needs of transporting blood and fluid in such areas as medical treatment and sanitation,theoretical analysis are applied to the pump and the governing equations of the pump are established,and the finite element method is employed to simulate the fluid flowing state in Y-shape tube and the whole pump.The pressure loss coefficients derived from the simulation results show a little difference from the experimental data,thus the correctness of the simulation is proved.The simulation results reveal that the pressure in the pump chamber varies calmly,and the pressure in the tubes eases off when the separation angel of two branch tubes increases, and there exists small vortex area at the intersections of the tubes and the pump chamber.Therefore,larger separation angel of two branch tubes should be employed and round corner should be made at the intersections of the tubes and the chamber during the process of making valveless piezoelectric pump with Y-shape tubes to decrease the votex in the pump.