Molding is an important process for thermoplastic composites to prepare products, and the surface quality of molding is an important reference for the overall quality evaluation of products. Based on the study of the basic characteristics of polyphenylene sulfide carbon fiber prepreg, this paper adopts the self-designed right angle mold and temperature control system to carry out the molding test of satin fabric prepreg and unidirectional prepreg, and comprehensively considers the influence of heating temperature, mold temperature, cooling time, pressure, ply and bending angle on the molding appearance. The results show that the prepreg is more conducive to resin impregnation in a specific temperature range, and it can keep a certain viscosity without outflow; The reasonable combination of cooling and pressure can make the molding surface more smooth and bright. The unidirectional prepreg layer will affect the surface quality of molding, while the fabric prepreg has little effect; During molding, the local shape change of the product is more likely to produce quality defects, and the excessive design of sharp corners or large curvature should be avoided as far as possible.