Abstract: To further improve the harmonic suppression performance of the 12-pulse rectifier, a low-harmonic multi-pulse rectifier with an auxiliary passive current wave-shaping circuit (PCWC) was proposed in this paper. The proposed multi-pulse rectifier included a conventional 12-pulse rectifier and a PCWC. The PCWC was installed at the DC-side of the 12-pulse rectifier, and it consisted of a modified inter-phase reactor (M-IPR) and two auxiliary single-phase rectifiers (ASRs). The synergy modulation of two ASRs increased the number of levels of the output current of the rectifier bridge from 1 to 4 first, which in turn extended the number of the input line current steps from 12 to 36 according to the ac and dc side current relationship. The resulting multi-pulse rectifier drew near sinusoidal input line currents with less than 5% THD from the utility. The proposed scheme only needed two low capacity ASRs, so it was a cost-effective, reliable and easy solution to harmonics pollution. An experimental prototype with a power of 2kW was built, and the correctness of the theoretical analysis was verified by simulation and experimental results.