Abstract: In order to improve the performance of micro piezoelectric generator, a design of flexible cantilever-beam piezoelectric generator was proposed. The influence of the beam's shapes and parameters on the output voltage of the piezoelectric generator, through theory and experiments was studied. Therefore a generator with appropriate structure parameters, such as length, width and substrate thickness will resonate easily on given wind speed, which helps to improve the power capacity of generator. Within a given wind speed range of 0 to 50 m/s, the power generating capacity of the flexible piezoelectric generator with different dimensions was researched. The experimental results imply that, the thickness of the substrate almost doesn't affect the power performance with resonance, but the length and width of generator has a greater influence on the output voltage, and the output voltage is not monotone increasing with the length and the width. The optimum length of piezoelectric generator is 40 mm, and the width is 11.3 mm.