To reduce the dependence of wool dyeing on the temperature several solvents with different properties and structures were added to the dye bath of C. I. Acid Yellow 42. Nearly the same total solubility parameters(${delta}_t$) of solvents as those of wool fiber and hydrophobic part of the dyestuff were needed to increase disaggregation of dye molecules, loosening the wool fiber and wickabilty of dyeing solution; besides, the large surface tension(${gamma}$) value of the solvents and the well balanced values of the three-component Hansen solubility parameters such as dispersion(${delta}_d$), polar(${delta}_p$), and hydrogen(${delta}_h$) bonding parameters were required. Among the added solvents dimethyl phthalate(DMP) and acetophenone(AP) were satisfied with these conditions and worked the most successfully in the low temperature wool dyeing. Their effectiveness proven by the dyeing rate and the activation energy ($E_a$) of the dyeing was in the order of DMP > AP > DBE > CH > M >NONE. In conclusion the total solubility parameters(${delta}_t$), the three-component Hansen parameters and the surface tension(${gamma}$) of DMP and AP could be the guidelines to select suitable solvents for low temperature wool dyeing.