In this paper, an improved current tracking method is established which is used in the three-phase -four-wire Vienna Rectifier. It aims at solving the back- ground harmonic and collapse voltage problems brought by the power grid. Meanwhile considering the poorish current tracking performance and precision in the conventional PI control strategy, a novel control strategy combined PI control strategy with the repetitive control strategy is put forward. In the paper, it makes qualitative analysis on the novel current tracking method, and it also does enough analysis and comparing about repetitive controller design. The superiority of the novel control method can be shown through contrast of two methods on harmonic suppression characteristics, and finally a experimental prototype of 3kW is built. The simulation and experimental results have proved the feasibility and effectiveness of the novel strategy. It has high tracking precision and it can also improve the wave quality of the input current effectively. When the distortion rate of grid current is reduced, the fluctuation of the output voltage is also slighter. So it can maintain perfect output characteristics.