In this study, the activity of imidazole ionic liquids is studied, and the influence of anion and cation function on this transesterification reaction is summarized. According to GC-MS analysis, the reaction mechanism is proposed. The transesterification efficiency is promoted by increasing the anion radius or shortening the alkyl substituent length of imidazole. The ionic liquid [Emim]IM prepared with imidazole ionic liquid and strong electron anion compound is used for the transesterification of ethylene carbonate (EC) with methanol to dimethyl carbonate (DMC). The catalytic activity is consistent with that of sodium methoxide due to the strong electronegative anion as well as weak interaction between cation and anion. The reaction equilibrium is realized in 1 min, together with 100% selectivity and 88.70% yield of DMC at 68 ℃ with only 0.3 % catalyst amount and EC∶MeOH = 1∶10. With gradually increasing the reaction temperature and MeOH content, the DMC yield raises. If the reaction was proceeded at 0 ℃, the as-synthesized catalyst still exhibited acceptable activity, which is in accordance with the results from the optimized [Mmim]I ionic liquid conducted. The 20 times re-use results without any inactivation indicated that [Emim]IM displayed excellent stability with 88%~90% DMC yield.