Abstract: The effects of sunshine, temperature, washing power and metallic ions on the natural brown cotton fiber were determined, also the mechanism of the effects was analyzed by studying the color turning of different densities or pH values aqueous solution of the natural brown cotton pigment, and by observing the chemical reactions of the pigment and metallic ions in the paper. Found out: the color traits of the natural brown cotton fiber, hue are located at 38 degree, saturation29%, and lightness53%. The factors such as sunshine, temperature, washing power and metallic ions influenced the color characteristics of the natural brown cotton fiber. The values of pH and the densities of the pigment affected the color properties of the pigment aqueous solution.