Abstract: Based on the assumption of hexagonal cross-section of yarns, a parameterized representative volume element (RVE) of 2D 1×1 biaxial braided composites was established with the consideration of the interaction and the cross-sectional deformation of the yarns. Coupled with the periodical boundary condition, the structural RVE was adopted to predict the elastic properties of the braided composites by the finite element method. The influences of braid angle and fiber volume fraction on the effective elastic constants were studied, and the overall stress distribution nephogram of the RVE under typical loads were obtained and analyzed. The results indicate tha the spatial configuration and the mutual squeezing of the yarns are validly reflected in the RVE, and the structural RVE with different structural parameters can be quickly regenerated, and the prediction results coincide with the experimental data well. The finite element model provides reasonable stress filed, which establishes a good foundation for structure optimization and failure analysis of the 2D braided composites.