Abstract: Micro valveless nozzle/diffuser pump is a diaphragm pump,which utilize the different pressure drop characteristics of flow through a diffuser and a nozzle to direct the flow in one preferential direction,and hence cause a net pumping direction.In order to increase the flow rate of the nozzle/diffuser pump,fin-shaped micronozzle/diffuser pump was developed in this work.Fluent was used to simulate the characteristics of fin-shaped micro-diffuser/nozzle pump,and optimized parameters were given.Measurement results show that the new design can improve the micronozzle/diffuser pumping performance of 11%.