Abstract: Three triazolyl ionic liquids, i.e., 1-butyl-3-methylimidazolium triazole(Bmim tr), N-methyl-N-n-butylmorpholinium triazole(Bmmo tr), N-n-butylpyridinium triazole(Bpy tr), were synthesized. It was found that ionic liquidBmim tr had good solubility performance for lignin dissolution,and the solubility was 58.61 g at 55℃ under microwave heating. The chemical structure, molecular weight, crystalline and morphology of regenerated lignin from microwave treatment were characterized by HSQC, FT-IR, GPC, XRD and SEM. The results indicated that microwave heating trends to cleavage hydrogen bonds and β-O-4' linkages, which accelerated the dissolution of lignin. And the basic structural unit of lignin was not destroyed in the dissolution process. The analysis showed that the dissolution mechanism of lignin in ionic liquid was the hydrogen bond damage and fracture of β-O-4' connection structure.