The thermal stability ,acid-resistance, alkali-resistance, oxidation-resistance, acid and alkali absorption of the soybean protein fibers were determined according to printing and dyeing process. It is to discuss in detail the effect of H_2O_2 bleaching process on the whiteness and strength of soybean protein fiber knitted fabrics. The optimum bleaching conditions are selected by orthogonal experiments. The result shows that the soybean protein fibers possess good chemical stability.