A valve-less piezoelectric pump with a Hemisphere-segment Bluff-body(HSBB) was designed by using a piezoelectric bimorph as exciting source. The structure and working principle of the piezoelectric pump were analyzed theoretically, then the finite element software was employed in simulating the flow fields of the pump. The theoretical analysis show that the positive and negative flow resistances of the pump are unequal, so the HSBBs can be used as no-moving parts in the pump. Finally, a sample pump based on the HSBB was fabricated and a series of HSBBs with different radiuses were produced. Some experiments on flow resistances and output flow rates of the pump were performed. The experiment results indicate that the time difference between the positive and negative flows decreases with increasing the pressure difference. The maximum flow rate of the pump obtained is 121.4 ml/min under a operating frequency of 17 Hz and the HSBB's radius of 4.0 mm. Moreover, the experiments give a relationship that the flow rate of the pump increases with the decreasing size of HSBB's radius during the unit time under keeping the peak-to-peak voltage of 150 V, which has a greater influence on the working efficiency of the pump.