To address the poor output issues of voltage quality and dynamic performance of inverters under nonlinear loads, a multi- voltage harmonics (MVH) control strategy is proposed based on traditional dual-loop control. Firstly, the mechanism of output voltage distortion in a three-phase four-wire inverter with dual-loop control under nonlinear loads is revealed, and the distribution characteristics of the output voltage harmonics in the inverter are analyzed. Secondly, a MVH control method is proposed for each phase inverter, in which each low order voltage harmonic is independently controlled in the corresponding synchronous coordinate system. Based on the characteristics of different voltage harmonics, a method for constructing the 3rd harmonic dq component of voltage based on the decoupled dual synchronous coordinate system and the 5th and 7th harmonic dq components of voltage based on the decoupled multi synchronous coordinate system are proposed to eliminate the AC component of each dq axis signal and improve the performance of voltage harmonic control. Then, a unified mathematical model of each voltage harmonic control loop is established in the static coordinate system, and the design method of the MVH controller parameters is analyzed. The output impedance characteristics and robustness of the proposed inverter control system are discussed. Finally, a 200 kVA T-type three-level inverter platform is built to verify the correctness and effectiveness of the proposed MVH control strategy by experimental results.