Optical behaviors and dyeing properties of color solution extracted from arrowroot leaves were investigated. The wavelength of maximum absorption of the color solution appeared at 268 and 320 nm, respectively. The amount of colors extracted was increased with extracting temperature and time. Spectra of color solution are shifted to longer wavelength at higher pH values, and shifted to shorter wavelength by irradiation for 2 hrs. Remaining ratio of colors by irradiation decreased with increasing alkalinity of color solution. Degree of exhaustion on the silk fabrics was related to the concentration and pH of dyebath. Surface color of dyed fabrics, lightfastness and wash-fastness were variously according to mordant used. Hot water resistance and drycleaning fastness of dyed silk fabrics by treatment of mordants were all within commercially acceptable limits.