The utilization of sustainable resources provides a path to relieving the problem of dependence on fossil resources. In this context, biomass materials have become a feasible substitute for petroleum-based materials. The development of biomass materials is booming and advanced biomass materials with various functional properties are used in many fields including medicine, electrochemistry, and environmental science. In recent years, ionic liquids have been widely used in biomass pretreatments and processing owing to their “green” characteristics and adjustable physicochemical properties. Thus, the effects of ionic liquids in biomass materials generation require further study. This review summarizes the multiple roles of ionic liquids in promoting the synthesis and application of advanced biomass materials as solvents, structural components, and modifiers. Finally, a prospective approach is proposed for producing additional higher-quality possibilities between ionic liquids and advanced biomass materials.