Abstract:  Based on Biot principle and Darcy's law , a two dimensional flow/compaction model and the finite element program was developed. The laminate deformation and pressure dist ribution can be predicted in the L-shaped laminates. Through comparison between the numerical and experimental data for thickness reduction of AS4 carbon fiber/epoxy 350126 laminate , the reliability of the numerical model and finite element program was validated. The laminate thickness variation was analyzed for 90° lay-up S-2 glass fiber/epoxy 648 laminates with the convex tool . It is found that the shear modulus has a significant effect on the laminate deformation at the corner and in the transition area between the flat and the corner sections. The length of flat part has a more obvious effect on the corner part deformation while relatively small influence on the flat section. The 90°lay-up S-2 glass fiber/epoxy 648 L-shaped laminates were fabricated with the autoclave process. The experimental data show that the cured laminate thickness is uneven with thicker corner and the flat part length affects the corner part thickness variation , which is consistent with the numerical results.