Keratin, regenerated from wool fibers, is widely used in the textile and medicine fields. In this work, a series of synthesized 1-butyl-3-methylimidazolium-based ionic liquids (IL) were used to dissolve wool keratin. Among these IL, 1-butyl-3-methylimidazolium dimethyl phosphate, [BMIM][DMP], is the best solvent; it can completely dissolve 5.0 wt% wool keratin in 10.5 h at 120 degrees C. In order to shorten the dissolution time, different cosolvents (sodium dodecyl sulfate, urea, and caprolactam) were utilized. Wool fibers at 5.0 wt% were dissolved under nitrogen within 4.5 h and a urea/[BMIM][DMP] mass ratio of 2.0 %, indicating that synergistic effects between the cosolvent and the IL can shorten the dissolution time. In addition, keratin regeneration was also studied. The results indicate that keratin regenerated in methanol shows better reproducibility and mechanical performance.