Abstract: The energy harvesting system for piezoelectric cantilever beam structure was modeled, the piezoelectric energy harvesting structure model was equated with the circuit system model by using the similar relationship between circuit system and mechanical system. To establish a complete model of piezoelectric energy harvesting system, the energy conversion circuit based on LTC3588-1 was equated with buck and rectifier circuit, the correctness of the equivalent circuit was verified by LTspice simulation. The whole model of piezoelectric energy harvesting system was built and simulated in Matlab/Simulink system, model parameters were optimized according to simulation results. Through the comparison and analysis of experimental data, the rationality of the system model was verified. The system can output 3.3 V DC voltage stably, and the output power is 2.6 mW under the optimal impedance matching condition.