Abstract: The brown pigment of cotton seeds coat was extracted and purified initially in this paper. There are two absorption peaks (231nm, 278nm) in its UV spectrum. The pigment color was affected evidently by pH values, but the pigment color kept stability at the same pH value. The pigment stability was not influenced by light, oxidants and reducing agents. Different metallic ions had different effects on the pigment stability .The pigment could be stable under 80℃.