The Piezoelectric bimorph with a concentrated mass attached at one end, an electric circuit for energy storage, and a rectifier that converts the AC output of the generator into a DC input for the storage circuit.In order to improve the energy conversion from the mechanical energy to electrical energy, piezoelectric power generator systems, which include piezoelectric structure, the rectifier circuit and the charging capacitor, are studied. In the experiments, the measurement results show that it exist a maximum output power corresponding to the optimal load in various capacitor C(subscript S) used case.