We observed that during the dyeing process of wild silk yarns with a reactive dye, dye uptake could occur in an alcohol-water solvent mixture bath that did not contain any salt. The K/S value of the wild silk yarn dyed by this process which is related to the dye uptake, increased with the increase of the alcohol content in the dye bath. At the some time, the K/S value was affected also by the kind of alcohol used. The effect on the K/S value decreased in the order of butyl alcohol, isopropyl alcohol and ethyl alcohol. However, if the solubility in water and the boiling point are taken into account, isopropyl alcohol was most suitable when a single alcohol was used. Even an alcohol with a low solubility in water could be used in the dye bath by combining it appropriately with isopropyl alcohol, and the K/S value could be improved. Based on the effect of the dye concentration, it appeared that dyeing in an alcohol-water solvent mixture was not suitable in terms of the dye buildup characteristics.