Aiming at the defects of cantilever piezoelectric power generation device, an I shaped piezoelectric generator is designed.The finite element model of the I beam generator is established and the static analysis and modal analysis are carried out. The results show that the maximum strain of I beam piezoelectric generator appears at each corner bending, and each corner bending has a consistent strain. Based on the piezoelectric equation, the maximum voltage will appear in the maximum strain, thus lead to the best generating capacity.Through the establishment of piezoelectric coupling analysis model, the output voltage is obtained,and every piece of piezoelectric patches will produce about 15.1 V voltages under the displacement of 0.1 mm.Finally, the parametric study of I beam piezoelectric generator is investigated to design the optimal structure, and to improve the generating performance. The results show that the power generating performance of I beam piezoelectric generator with 80 mm long, 15 mm wide, and 0.4 mm thick pressure electrician form board is best, and the maximum voltage can be up to 16.5 V.