Recent concerns about the gradual depletion of conventional fossil resources and the pressure from global climate change have accentuated the need for new alternative feedstock. As one of the main components in biomass, lignin is the second most abundant natural polymer after cellulose, and has the potential to serve as a sustainable source of energy and organic carbon to replace petroleum-based chemicals. Efficient conversion of lignin into high value-added chemicals is crucial to improve the economic feasibility of biomass refinery. In the present study, several pretreatment technologies on industrial lignin were carried out to enhance phenol production. A microwave irradiation assisted biphasic reaction system was used to convert pretreated industrial lignin into phenolic compounds. Lignin conversion, reaction temperature, time and pretreatment method, were optimized. The highest phenol yield was 8.14% obtained from lignin pretreated by 1- ethyl -3-methylimidazolium acetate at 400 W for 60 min in a biophasic system catalyze by 1-aminoethyl-3-methylimidazolium tetrafluoroborate.