Magnetic-bias control technology is one of the key issues in the field of single-stage PFC dual-transistor forward converter. Expounds the damage induced by magnetic bias and analyzes the bias phenomenon causes in single-stage PFC dual-transistor forward converter. Puts forward a reasonable and effective bias control circuit scheme, explains its working process and principle, and produces a test board of the converter, in which sets the on and off nodes on the main circuit and bias control circuit. Makes contrast experiments and verifies the feasibility and effectiveness of the proposed converter.