Abstract: Dyeing properties of wool yarns treated by ionic liquids prepared in our lab was studied. The results show that dyeing rates of wool treated by ILs are increased in some degree, and in the same treatment condition, equilibrium exhaustion of wool treated by [Emim]Ac at 60 ℃ for 10min reaches 93.95%, while equilibrium exhaustion of wool untreated reaches only 78.9%, that wool yarns treated by [Emim]Ac at 60 ℃ for 10min have good low temperature dyeing, and that wool yarns treated by ILs which have better dyeability have lower tensile strength. SEM shows treatments of various ILs have great effects on surface structure of wool fiber.