With the aim to measure and study the electricity generating performance of Piezoelectric Ceramics(PEC),a measuring system for the electricity generating capacity of the PEC is developed. A piezoelectric cantilever dibrator is designed and the effect of Optimal Thickness Ratios(ORT) of the PEC to the metal plate on the piezoelectric dibrator is analyzed by Finite Element Method(FEM). The results show that the output voltages and power are maximal at the resonance frequency. The ORT of the piezoelectric cantilever dibrator is 0.5 obtained by FEM,which is consistent with the experimental results. Moreover,the output voltages of the piezoelectric cantilever increase as the resistive load increases,and the voltage approaches to 5.4 V when the resistive load is 50 kΩ. Nevertheless,the electrical power decreases when the load resistances are further increased,and the maximal output power is about 1.18 mW from the piezoelectric cantilever in a resistive load of 10 kΩ at the resonance frequency.Experiments show this power level is high enough for some wireless communication systems.