Abstract: Silk/cotton fabric was modified by color media and achieved dyeing of reactive dye without salt and alkali in one bath. The different reactive dye were applied to dyeing of silk/cotton in one both and optimized to obtained trichromatic reactive dyes for dyeing of silk/cotton in one both by analyzed the balance value of union dyeing K and color-difference ?E. The dosages of Color Media, temperature and time were discussed to affect on dyeing in one bath of silk/cotton fabric, and the optimal modified process was obtained by orthogonal experiment design. The results indicate that the ratio of dye-uptake and fixation, union dyeing property and strength reserved ratio of fibre were increased obviously and color fastness was not decreased by compared traditional dyeing.