Piezoelectric vibration energy harvester is the important component of wireless self-power supply for low-power electronic products, and its coupling mechanism with nonlinear power extraction circuit is the key theory to improve the output performance of the wireless self-power supply system. Taking the nonlinear tristable piezoelectric vibration energy harvester and four different power extraction circuits as the object, the coupling dynamic model of the presented system is firstly formulated, and the steady state solutions of the coupled dynamic response of the system under different interface circuits are obtained by using the harmonic balance method. The effects of system parameters on the output characteristics of the interface circuit are simulated and analyzed. Results show that when the electromechanical coupling coefficient is too small, the S-SSHI circuit is suitable for occasions with frequency less than 7 Hz and load resistance less than 7. 4 × 10 6 Ω, while P-SSHI circuit is opposite. The DC circuit has advantages when electromechanical coupling coefficient is too large, and the output power is 4. 5×10 -3 mW. AC and DC circuits have a wide range of electromechanical coupling coefficients, while P-SSHI and S-SSHI circuits have a narrow range but have high output power, and the maximum output power can reach 19. 0×10 -3 and 14. 3×10 -3 mW. The simulation results are verified by experiments.