This study was carried out to investigate K/S values, surface color, the fastness to washing, bacteria reduction rate of the silk and cotton fabrics dyed with Rhus verniciflua extract under the various dyeing conditions. The optimum dyeing temperature, dyeing time, dyeing pH and repetition of the silk fabrics dyed with Rhus verniciflua extract were $l00^{circ}C, 30min., pH 5, five times repetition respectively, but in the cotton fabrics, it were $60^{circ}C . 30min., pH 7, one times repetition. It were colored orangish Yellow in the silk fabrics and colored bright yellow in the cotton fabrics dyed with Rhus verniciflua extract. Surface color(munsell value) was not changed by the mordanting agents but those of the silk showed high tone when mordanting with stannous chloride, and it was decolored and darked when mordanting with ferric sulfate. The fastness to washing in the silk fabrics dyed with mordanting agents improved in 4～5 grade, but the cotton fabrics were 3～4 grade, so washing fastness of the silk and cotton fabrics were significantly improved when washing with the neutral detergent. The bacteria reduction rate of the silk fabrics increased drastically by dyeing of Rhus verniciflua extract.