Natural dyes are environmentally and human compatible. But they are not various or not fast in color. The mixed dyeing have been attempted to solve these disadventages of natural dyes. The persimmon juice dyed fabrics have brown-color and good hygienic properities however low color fastness. The onion dyeing show similar brown-color and have good color fastness caused by querectin existed in onion outer skins. Mixed dyeing was carryied out on silk fabrics using persimmion juice and onion outer skin extract in this study. The mixing method were persimmon juice dyeing and then onion dyeing(P-O), onion dyeing and then persimmon juice dyeing(O-P) and dyeing in the mixture of persimmon juice and onion outer skin extract simultaneously(P+O). The mordants were none-mordent, gallic acid after-treatment and alum after-treatment. Several persimmon juice dyed fabrics were irradiated for 2 hours before onion dyeing(PU-O). The color values of dyed silk fabrics were as follows. The persimmon juice dyed silk fabric developed to yellow-red color after 2 hours of uv irradiation. Onion dyed fabrics show similar yellow-red color after dyeing without uv irradiation. The effect of alum after-treatment on color difference were highest in onion dyeing. The dyeabilities of both P-O and O-P were higher than persimmom juice dyeing and onion dyeing. The dyeabilities of P+O was lower than persimmom juice dyeing and onion dyeing. The value of color difference of alum-treated fabric was the highest. The color difference of P-O and O-P caused from 2 to 4 hours of uv-irradiation were lower than those of persimmon juice dyed fabrics. Onion skin extract could prevent the color-change of persimmon juice dyed fabrics in mixed dyeing. The color difference of PU-O was higher than the P-O.