The nonlinear vibration characters of the bistable piezoelectric power generation system were investigated. Adopting the harmonic balance method, the equation of amplitude-frequency was derived. The effects of different nonlinear coefficient, the impedance parameters and excitation were analyzed. With changing of frequency and force amplitude, the jump and multiple solutions phenomenon were observed. The minimum unstable area was obtained by varying the nonlinear coefficient and the impedance parameters. Then, the influence of excitation on the power was analyzed, with the nonlinear coefficient and impedance parameters increase, the output power first increase and then decrease, the maximum power was get by adjusting the magnetization and the load impedance. At last, the voltage frequency response curves and the power resistance response curves obtained through experiments verify the system’s nonlinear characters. The results provide theory evidence for engineering application.