The work is devoted to the design with specified properties and production technology of suit fabrics. The criterion of fabric structure evaluation is air permeability, which determines quantitative and qualitative evaluation of fabric structure.The technique of designing of clothing (costume) fabrics according to the given air permeability is developed, in particular, the air permeability coefficient, the percentage of unfilled and filled with fibrous material of fabric area, the average yarn number (linear density), fabric density and the equation of air permeability for the given fabric are determined.The difference between experimental values of air permeability and calculated values of air permeability is determined. The equation of air permeability coefficient of square fabric is proposed, taking into account the sum of numerator and denominator fractions of the main weaves.The research of parameters of square fabric structure depending on the weave, air permeability and surface density of the fabric is carried out.