By analyzing the forming process of paper-plastic composite bags, the paper clarifies the demand for correction in the production of composite bags from the defects of positional deviation and tilt in the production of paper-plastic composite bags. And it is necessary to prevent the paper-plastic composite bag from wrinkling due to improper belt pressure during the correction process. The paper establishes the finite element model of the composite bag based on the theory of thin plate buckling, use the buckling analysis tool in Ansys Workbench to simulate the paper-plastic composite bag in various postures, and solve the maximum buckling load of the belt. Finally, the maximum positive pressure to the belt can be obtainedaccording to the maximum buckling load equal to the composite. When the belt spacing is 50 cm, the maximum belt positive pressure is the largest, that is, the paper plastic composite bag can bear the maximum friction, and the error between the trajectory and the theoretical trajectory is smaller. The calculation result is accurate and the data is sufficient to meet the control requirements of positive pressure in correction.