The work aims to discuss and design a packaging structure and process formed by folding the flexible packaging, aiming at the problem that the lower film of the existing thermoformed vacuum packaging product cannot be pre-printed and need to be labeled. In the method of corner folding forming, the packaging structure was composed of upper and lower films. The lower film was fixed by corner folding point, and the parametric design of lower film was conducted. The tangential function relationship between the longitudinal folding shrinkage and the folding angle was obtained. When the folding angle was 90°, the longitudinal folding shrinkage was the largest. The functional relationship between the pushing angle and the angle was obtained. The resulted showed that, when the ratio of the folding angle was constant, the folding angle gradually decreased with the increase of the pushing angle. The relationship between the corner folding parameters is solved and a folding process scheme is provided. The process includes longitudinal folding forming, corner folding, lateral folding forming, corner sealing, filling products, vacuum heat sealing and die cutting. The theoretical support is provided for the realization of automated packaging and production of products.