Abstract: An analysis model based on the microstructure and the stiffness averaging method is established to predict the elastic constants of 2-D braided composites. The computer software based on the model of the 2-D biaxial braided composite was compiled. The elastic performances of braided composites were studied, and many useful results that can be used in structures designing were obtained. The effects of braiding structure parameters on the elastic properties of composites were also analyzed. Comparing the relevant predictions with the experimental results validates the model presented. The comparison shows that there is good agreement for the elastic properties and it can be used in the engineering design.