Recently, the auxetic fabrics have gained much importance in the scientific and industrial community due to their excellent impact-resistance property. Due to this property, they have several applications, including automotive, aerospace, and ballistic areas. The auxetic three-dimensional (3D) woven fabrics are a less explored domain in the auxetic community. Herein, special attention is given to the numerical analysis of the 3D auxetic structure. The negative Poisson's ratio of 3D auxetic structures is studied using ANSYS workbench structural analysis module. The effect of binding yarn float length on negative Poisson's ratio is tested on ten different 3D orthogonal through the thickness structures with binding yarn float length of 1:1, 2:1, and 3:1. Furthermore, the effect of the number of binding yarns and the number of layers is also studied numerically. The results show that the auxeticity of the woven structure increases with increasing the number of binding yarns and their float length. Moreover, decreasing the number of layers from 3 to 1 increases the auxeticity.