Abstract: In order to make the lapel and collar band brought fold accurate, simple structure, even the lapel fold freely, keep attractive appearance, this study through direct drawing method, according to Japanese culture bodice prototype for garment body, using different bust, different collar band and collar concave, draft turndown collar. It make 96 pieces collar sample, try on the standards body mold, confirm the center point of collar, measure lapel and collar band, then analyse change rules of lapel structure, carry out correlation analysis and regression analysis, establish of mathematical model of over-turned collar Concave structure. It will realize lapel structure scientific and simple. It will provide pattern experience for technical personnel, and provide basic structure for intelligent CAD pattern system.