Abstract: A three-dimensional thermal-chemical-stress coupling numerical model was developed for the hot-pressing process of composites. Thermo-chemical strain，viscoelastic behavior，anisotropy，glass transition temperature related to the cure were fully considered during the autoclave cycle. The model was numerically solved by FEM，fully coupled for thermal-chemical model and one way coupled for the stress model. The results of AS4/3501-6 composite laminate show  good agreement in simulated curvature with experimental results.The numerical results reveal that reducing the thickness or increasing the length of the laminate causes the curvature deformation to grow up. The autoclave pressure has little influence on the curvature deformation. The smaller the difference of the coefficient of thermal expansion(CTE) between tool and laminate，the smaller the curvature deformation.