To investigate the green trinitration method of aromatic compounds, with Lewis acid/ionic liquid as catalyst and HNO3/Ac2O as nitration reagent, a Lewis acid/ionic liquid/HNO3/Ac2O system was established. In various combinations of Lewis acids and ionic liquids, Bi(NO3)3 center dot 5H(2)O/[HMIM]ClO4 proved to be a very efficient catalyst for the trinitration of activated aromatic compounds and reusable for 3 times. Reaction conditions for the trinitration were optimized and yields of the trinitro products were from mild to excellent. This sulfuric acid-free system has the advantages of strong trinitration ability, low environment pollution, low toxicity, low cost and high potential for industrial application.