Abstract: When the power grid is unbalanced, the three-phase Vienna rectifiers mostly control the positive and negative sequence components by using the grid side voltage delay of 90° or the positive and negative sequence separation methods. Controlling the positive and negative sequence components separately increases the control system complexity and reduces the control effect. Therefore, this paper proposes a control strategy for Vienna rectifier's voltage reconfiguration in an unbalanced power grid. By reconfigurating the voltage on the grid side, the reference voltage put into the inner ring becomes the balanced voltage, and the Vienna rectifier will run steadily. In the current inner loop, several quasi-proportional resonance controllers are cascaded, realizing the non-static error tracking of the current controllers and suppressing multiple harmonic components, which will improve the input current total harmonic distortion (THD)of the network side. In the DC side voltage outer loop, the sliding mode control is adopted to overcome the complexity of PI controller parameter setting and the hypersonic problems. At the same time, this control has also a good transient and steady-state performance under the condition of an unbalanced power grid. Finally, the simulation analysis is carried out in the Simulink and the experimental platform is built for verification. The results show that the control strategy reduces the harmonic content of the input current at the network side and improves the anti-interference performance of the Vienna rectifier with good robustness and stability.