As one kind of promising zero-dimensional nanomaterials, carbon dots (CDs) have attracted extensive attention recently in green chemistry and engineering on account of their excellent properties, such as water solubility, comparable optical properties, low toxicity, and surface passivation and functionalization. One direction in CDs research is to prepare these materials with low cost and high quantum yield (QY). As an alternative protocol, utilizing biomass or its derivatives as the raw materials would create more chances to produce biocompatible and cheap CDs. Due to the good solvability for biomass, various ionic liquids (ILs) have been tested in the field of biomass derived CDs, which are found multiple roles of solvation and surface functionalization in the synthesis and application of these materials. This review will not cover the whole developed picture of CDs, but just summarizes the latest research progresses on the ILs based preparation and applications of CDs from biomass and its derivatives. The roles of ILs displayed in the corresponding processing including intensification and surface modification were discussed in detail. At the end of this review, an outlook was provided to highlight the challenges and opportunities associated with this interesting and promising area.