In this study, testing materials were prepared with 100 kinds of weft knitted fabrics on sales which plain, 1 $ imes$ 1 rib, interlock and airmery stitch consisted by different yarn count Ne 30, 40, 45, 50 and 60. The relationship between thermal resistance of weft knitted fabrics and structural parameter by statistical analysis was discussed. The regression equations could be obtained between thickness and yarn count of weft knitted fabrics by means of multicuervilinear regression analysis. The results were as follows. , where R=thermal resistance of the knitted fabries(mm), T=thickness of knitted fabrics(mm), C=count of knitted fabrics(Ne).