The work aims to propose a double belt differential correction method, in order to reduce the inclination of the compound bag on the sewing station and improve the sewing quality. In this method, two belts with different speeds were used for the turning of the compound bag, and the compound bag was straightened before the sewing station. Through experiments, the best correction speed and turning radius under different offsets were measured discretely, and the corresponding correction speed and turning radius of continuous offsets were calculated by fuzzy control algorithm. Through the Matlab simulation correction algorithm, the trajectory of the compound bag met the expected correction path, and the deviation of 50 mm was corrected within 15 seconds, and the correction error was less than 1 mm, which met the industrial requirements. The double belt differential correction method can not only be applied to paper plastic compound bags, but also be well applied to the correction of industrial flexible body, filling the gap in the field of flexible body correction.