The response characteristics of bistable piezoelectric power generation system under white noise excitation are studied. Fristly, Gaussian white noise is simulated by montecarlo method. Then, the effect of noise intensity, load impedance and initial value on the system response under random excitation is studied numerically and experimentally. The results show that the time interval of the jump between two equilibrium points is reduced as the noise intensity increasing. The initial value and impedance will influence motion of the system, being proved by drawing the attraction domain of large amplitude motion. At the load impedance about 19.1 kΩ, the output power has a maximum.