Abstract: Designing the looseness of a lapel collar is not an easy work.In this research,the impact of the fabric performance on the rule of looseness of lapel collar is studied.Six kinds of fabrics commonly used for suits are chosen,and 16 mechanical properties of them are tested by KES-FB system respectively.Principal component analysis of the data obtained is conducted by SAS software,minimizing the variables from 16 to 3,i.e.,tensile recovery(RT),compressive resiliency(RC) and weight per unit area(W) of the fabric.Then,5 kinds of lapel collars are made with 6 kinds of fabrics.The length of the collar stand is(2.5 cm) without exception,while the width of the top collar is in the order 3.5,4.5,5.5,6.5,7.5 cm,and the relevant difference of top collar and collar stand width(H) is 1,2,3,4,5 cm.The suitable looseness is found out for each collar.Finally,the correlation of RT,RC,W,H and the looseness is investigated by regression analysis with SAS software,and some quantitative relationship is found.