Abstract: A kind of five-level inverter double-band SHEPWM control method was proposed combining Walsh transformation with SHEPWM program which can broaden modulation ratio of multi-level inverter. Multi-level multi-band SHEPWM voltage waveform based on Fourier series transform was analyzed, and general forms of SHEPWM nonlinear equations under each band mode were summarized. Then nonlinear equations were changed into piecewise linear equations easy to solve, so as to simplify calculation process and broaden modulation ratio. Taking five-level inverter with H-bridge cascade as an example, piecewise linear equations of Walsh function under A and B band mode were given. Correctness and feasibility of five-level inverter double-band SHEPWM control method were verified through experiment, which established foundation for realization of online computing and real-time control of SHEPWM technology.