The energy harvesting systems of piezoelectric material are investigated in this subject. These research is also cooperative with Malaysian scholar, Dr. Z.C. Ong and Dr. S.Y. Khoo. The piezoceramic plate, bimorphs, and disks are used to perform the vibration characteristics by experimental measurements and finite element method (FEM). Thereafter, the dynamic characteristics and the electromechanical coupling efficiency of the piezoelectric energy harvesting system are studied by the electrode design method of the single-layer piezoceramic plate and by series electrically connection of piezoelectric bimorphs and disks with different polarizations. This study thoroughly analyzed vibration dynamic characteristics of piezoelectric materials by experimental measurements and numerical calculations. Several experimental techniques are used to measure the dynamic characteristics of piezoelectric materials. First, the full-filed optical technique, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI), can measure simultaneously the resonant frequencies and mode shapes for out-of-plane and in-plane vibrations. Second, the pointwise measurement system, laser Doppler vibrometer (LDV), can obtain resonant frequencies by dynamic signal swept-sine analysis. Third, the correspondent in-plane resonant frequencies and anti-resonant frequencies are obtained by impedance analysis. The experimental results of vibration characteristics are verified with numerical calculations. After the dynamic characteristics of piezoelectric materials are analyzed in converse piezoelectric effect, the piezoelectric materials are excited by shaker to generate the electric voltage and applied on the stimulation of LED. It has excellent consistence between resonant frequencies and mode shapes on the vibration characteristics by experimental measurements and finite element numerical calculations. In this study, the Electrical Potential Gradient (EPG) calculated by FEM is proposed to evaluate the electromechanical coupling efficiency of piezoceramic plate on the specific vibration mode. The correspondent electrode configuration, which is designed by EPG, can produce the best electromechanical transfer both in direct and converse piezoelectric effects. Finally, the series piezoelectric bimorpf in series connection shows the best output of electric voltage and light intensity of LED, than the case of parallel piezoelectric bimorph in series connection and single-layer piezoceramic plate. It is concluded that the vibration characteristics of piezoelectric materials have excellent consistence determined by experimental measurements and FEM.