In response to the relationship between perform structural parameters and the composites properties, a newly geometrical modeling of 2D biaxial orthogonal woven fabric was established in this paper. Based on the yarn’s true configuration, the SEM image of the yarn cross-section was taken, geometrical parameters (the individual tow geometry and weaving pattern of the fabrics) are introduced in order to describe the general families of woven fabrics. The tow waviness can be described by combinations between undulated and straight segments and the tow cross-section can be described by lenticular shape. When the geometrical model was used to predict the structural properties of the fabric, the predicted values show good agreement with the measured ones. The geometrical model proposed here is intended as the foundation for further design and analytical of the mechanical properties of the composite materials reinforced with these fabrics.