Aiming at the problems of fold and deviation of paper-plastic composite bag in the process of transmission, a paper-plastic composite bag deviation correction system based on magnetic pressing device was proposed in this paper. The deformation of paper-plastic composite bag under the influence of multi-factors was analyzed to guide and improve the deviation correction system. Firstly, the deviation correction system was designed according to the principle of magnetic pressure. Then, the deformation of paper-plastic composite bag was simulated based on the explicit dynamic finite element contact theory. Finally, an experimental platform was set up and the deformation of the paper-plastic composite bag was measured to verify the simulation results. The optimum scheme is as follows:the dynamic friction coefficient between paper-plastic composite bag and belt is 0.25, the magnetic pressure is 7 N, the distance between belts is 476 mm. The experimental results obtained by the platform are basically consistent with the simulation results. Based on the experimental results, the improved magnetic deviation correction system can be applied to the deviation correcting of paper-plastic composite bags to meet the needs of industrial production.