The purpose of this study is to mesure the optimum pH, the optimum temperature, and the optimum concentration of hydrogen peroxide, in the blenching of spun silk fabrics with hydrogen peroxide, to examine the effect of sodium silicate as a stabilizer on breaking strength and reflectance, and to investigate the effect of fluorescent agents in the oxidation reaction of bleaching solution. The above mentioned experiment, however removed the polyene pigments in silk through changing them into organic acid by oxidation. The results of the experiments tested by I.R. spectrum showed that only pigments were removed in a short time without damaging the property of silk.