In this paper, we analyze the mechanical interaction of warp and weft yarns in shearing deformation, and establish theoretical equations expressing the relationship between the shearing rigidity and the fabric structures. To avoid calculating the rate of friction change during shearing deformation, we use KES data for twenty-seven worsted fabrics to create the empirical equations that describe the relationship between the rate of friction change and the contact area of yarns. By combining the theoretical and experimental equations, we develop equations for predicting the shearing rigidity of short-float worsted fabrics based on simple fabric structural data. Another set of worsted fabrics is used to validate the prediction equations.