Abstract: The Anti-phase winding method is an effective method to suppress the conducted common mode noise of boost converter, but there are many factors that affect the noise suppression ability of the anti-phase winding method, and the influence mechanism is complex. At present, there is no clear method to optimize the design of the anti-phase winding. For large turn ratio anti-phase winding method, based on the analysis of the equivalent model of common mode noise, the mathematical model of insertion loss of the method was established. Based on the mathematical model of insertion loss, it was clear that the compensation capacitance, leakage inductance and the number of turns in the Anti-phase winding were the key factors affecting the noise suppression ability of the large turn ratio Anti-phase winding. On this basis, the design method of the anti-phase winding method based on the principle of the best effect of the low-frequency common mode noise suppression was proposed. By optimizing the compensation capacitance, reducing the leakage inductance and increasing the ratio of the equivalent turn ratio of Anti-phase winding to the leakage inductance, the effective frequency bandwidth of the reverse winding method could be expanded, and the common mode noise suppression ability of the reverse winding method could be greatly improved. The experimental results show that the proposed anti-phase winding design method can effectively suppress the conduction common mode noise in boost converters.