Abstract: This study analyzed the dynamic amount of deformation of half-waistline of young men aged 20-30 in the region of East China using the statistical method named general statistical and K-means,and the total tendency of half-waist′s movement change was obtained by means of statistical software SPSS.This paper used the grey theory GM(1,1) and math software MatLab to build the optimized mathematics model of the law of change and the amount of deformation of half-waistline for each motion.The experiments revealed that the model′s simulated data was in good agreement with the actual data and it would offer reference value for the research of motive comfort in lower garment design.