The low-cost, simple structured micropump which is actuated by piezoelectric-discs, is fabricated with polydimethylsiloxane and the performances of the micropump, such as pump rate and backpressure, are characterized. As a flow-rectifying element, the diffusers are used instead of passive check valves. The glass diaphragm deflection of micropump measured by atomic force microscope is about 0.4 μm when applying a 150 V square wave voltage at 300 Hz across a 300 μm thick piezoelectric-disc. The flow rate of micropump increase with enhancing the applied voltage to piezoelectric-disc due to the increase of diaphragm deflection. The flow rate and the backpressure of the micropump with diffusers are about 32.9 μl/min and 173 Pa when applying a 150 V square wave driving voltage at 300 Hz across a 300 μm thick piezoelectric-disc.