Friedel-Crafts acylation of aromatic compounds has been an important reaction in the production of aryl ketones, which are important intermediates in the production of pharmaceuticals and fine chemicals. Many clean solvents like water, ionic liquids, supercritical fluid, polyglycol, fluorine-containing solvents, and so on are employed to replace the conventional organic solvents. Among these, ionic liquids have attracted considerable attention as the clean designable solvents. Ionic liquids received global attention not only in the academic fields but also in the industrial circles. So far, the normal ionic liquids as the clean solvents, and the functional ionic liquids as the special clean solvents (e.g., chiral solvents), the catalysts, and the supports for reagents as well, have been applied extensively in many organic reactions, such as the alkylation, acylation, esterification, rearrangement, hydroformylation, coupling reactions, Diels-Alder reactions, asymmetric synthesis, and so on. This paper mainly reviews the role of the ionic liquids as the green solvent and catalyst for Friedel-Crafts acylation reactions.