In recent years, seismic wave impedance inversion method plays an important role in reservoir prediction, which is the primary technology to ensure the proper integration of seismic data, well-logs, velocity and geological information. In this paper, the authors analyzed and contrasted of the key technology and applicability of five types seismic wave impedance inversion methods commonly used in petroleum industry. Furthermore, the authors presented a thought for seismic inversion called three stages and nine steps inversion method.