Based on the photographic observation and analysis of different cross section of the materials, it is found that both the section of normal and warp yarns are rectangular in shape, the sections of weft yarns are the convex lens in shape, the weft and normal yarns are kept straight along their directions, the warp yarns are wavy. 3D images and geometry model of normal yarns reinforced 2.5D woven materials are established. This model can be used to calculate the fiber volume fraction of each yarn system. Compared with the experimental data, the computational results show excellent agreement. The work will lay the foundation for prediction of mechanical properties.