A new type of piezoelectric system was designed, which includes a cantilever beam, a piezoelectric plate, a magnet and a drive motor based on the piezoelectric effect. And through the optimization of the power generation performance, the system was applied to the bicycle warning lamp device and used as an independent power supply system. Firstly, the stress and dynamics of the piezoelectric cantilever beam was analyzed by ANSYS, and the influence of the size on the performance of power generation was discussed. Then the rotation of the disc and the magnetic force were used to make the piezoelectric cantilever bend and increase its amplitude. Furthermore, the circuit analysis experiment was carried out to study the effects of different pitch and speed of magnet on the output voltage. The results show that: when the wheel speed was 240 r/min and the magnet spacing was 15 mm, the output voltage of piezoelectric system which is mounted on the bicycle can reach to 4.42 volts. And the LED lamp can keep stable, and the light condition can be taken as a bicycle night warning light.