In need of studies on the kinds and structure of thread, the biggest variable factor in knitwear patterns, this study attempts: to examine the physical properties by thread type to basically establish systematic data in order to utilize various mixture and structure of yarn and to contribute to the development of optical patterns by building a systemic and scientific methods to produce knit wear patterns though a statistical analysis of the relation between the variations and physical properties. The results is as follows: with time, a feature of knit, which causes instability making it difficult to maintain the original shape, related to material properties, the weight and expansibility recovery rate have the greatest influence on the variation of wale lengths, though the amount varies by material. The variation of course contraction is closely related to density, the dense fabrics showing the highest values, due to the bust of the human body, the wale length variation of the front is greater than that of the back, by a regression analysis of material properties and the variations is obtained showing the weight, density and expansibility recovery rate have the greatest influence on the wale extension and course contraction of knit.