Abstract: The applications of wool blend fabric in the clothing increased in a wide range.This studies use flat seam shrinkage as point of penetration,research on the factors which impact the flat seam shrinkage of wool blend fabric.Through multi-experiments and large data analysis, to found The pertinence of wool blended fabric's flat seam shrinkage and the fabric thickness,The pertinence of wool blended fabric's flat seam shrinkage and the fabric softness, The pertinence of wool blended fabric's flat seam shrinkage and the length of needle gage,The pertinence of wool blended fabric's flat seam shrinkage and Thickness of sewing thread. This research can be use on the production of clothing which made by wool blended fabrics, help the producer improve the quality of this clothing.