In one dyeing system of silk/synthetic blend fabrics (polyester, nylon, acetate) with acid dyes/disperse dyes, dyeability and desorptibility of disperse dyes on silk fabric and transfer from dyed silk fabrics to synthetic fabrics by color difference were examined. When silk dyed with C.I. Disperse Red 19 and C.I. Disperse Red 60 at 10$0^{circ}C$ for 60 minutes, color difference of dyed silk were $Delta$E=56.72, $Delta$E=47.65 for blank silk, respectively. The desorption rate of the dyed silks were measured in boiling bath with and without dye-free synthetic fibers. The desorption rate of dyed silk was effected by affinity of synthetic fabrics contained. When silk dyed with Red 19 and Red 60 was reduced at 10$0^{circ}C$ for 60 minutes, the decolouration rates of dyed silk were 75% and 40%, respecdtively.