Abstract: Abstract: In order to observation on the fiber color traits of filial generation , cross experiments between the dark brown cotton and white cotton were preformatted. Also the contents of pigment in the cotton fiber were determined. The results indicated the fiber color of first filial generation between the male parent and female parent, and fiber color of second filial generation could be divided into three types: dark brown, middle brown and white. The color and pigment contents of dark brown fiber, middle brown type in second filial generation respectively neared to that of parent dark brown fiber and first filial generation. The ratio between three types of second filial generation was conformed to 1:2:1 tested by Chi-Square (p >0.05). So we claimed the inheritance mode of fiber color was incomplete dominance. The relations between the qualitative traits and the modificator gene were discussed in the paper. The tests would contribute to breeding of naturally colored cotton and new color varieties cultivating.