The indigo dyeing on silk was carried out by the use of fresh leaves juice of polygonum tinctorium. By means of spectroscopic analysis, it is proved that indoxyl are present in the juicese due to the enzymatic reducing of indican contained in the leaves. In case of fresh leaf dyeing, K/S value of dyed fabric was higher at 25$^{C}$ than at 35$^{C}$ of the dyeing temperature, its colour fastness aganist washing, perspiration and ligt ranged from 4 to 5 grade.