The fabric, 100% Silk, was dyed with Atractylodes japonica extract solution. The effects of concentration of extracts (colorant), temperature of dyeing, time of dyeing and pH of dye bath were studied. As the concentration of extracts increased, color strength (K/S value) increased progressively. The K/S values increased with raising temperature, time and proper conditions were $80^{circ}C$ and 80 minutes. Maximum K/S value was obtained at pH 3. The K/S values of mordanted fabrics were increased with increasing mordant concentration up to specific values. Surface color of dyed and mordanted fabrics were yellowish. Light color fastness of fabric with mordanting was fairly good 3/4 rating. The mordanted silk fabrics showed excellent antibacterial activity. The silk fabric dyed with Atractylodes japonica extract showed a superior UV protective property.