Abstract: Python language was used to redevelop ABAQUS to generate 2D plane strain model with randomly distributed chopped carbon fibers. The representative volume element(RVE) was created and meshed with Hypermesh. In order to ensure the uniform coordination of the stress field of the RVE, the numerical simulation analysis of the tensile properties was under periodic boundary conditions, and the change trend of the effect of fiber length on the elastic modulus of the sheet molding compound was studied. The results verify that the tensile modulus of chopped carbon fiber/vinyl ester resin sheet molding compounds increases first and then decreases gradually with the increase of fiber length, and it is right to use Python-ABAQUS to establish a 2D plane strain RVE model. This study provides theoretical and experimental basis for the application of sheet molding compound in the automotive lightmass industry.