A kind of piezoelectric resonant diaphragm air pump was proposed, which is based on the system resonant principle. Firstly, the working principle of the piezoelectric resonant diaphragm air pump was analyzed and a dynamic model of the pump resonance was established. The main factors of the output flow rate can be obtained. Then a prototype was designed. The testing facility was developed to measure the volume of the resonance pump. Finally, the variation of output flow rate on different vibrating spring rate, adjusting spring rate and diaphragm rate were obtained by experiment test. Experimental results indicated that the maximum flow rate was 1650 mL/min when he sinusoidal AC driving voltage was 150 V, the vibrating spring thickness was 0.6 mm, the adjusting spring thickness was 1.4 mm, and the radius ratio of the rigidity transfer vibration piston and the diaphragm was 0.5. And the amplification factor of the piezoelectric vibrator was 5.3 by using the proposed photovoltaic displacement sensor. 