The kinetic behavior and chemical equilibria for the transesterification of methyl acetate with ethanol to ethyl acetate and methanol catalyzed by an ionic liquid 4-(3-methyl-1-imidazolio)-1-butanesulfonic acid hydrogen sulfate ([HSO3-bmim]HSO4) were studied experimentally. The relationship of chemical equilibrium constants versus temperature was obtained from kinetic experimental data. The effects of temperature, initial molar ratio of ethanol to methyl acetate, and catalyst concentrations were investigated. Based on the reaction mechanism, an ideal homogeneous (IH) and two nonideal homogeneous models (NIH-1, NIH-2) were proposed to correlate the reaction kinetic data. The activity coefficient of the catalyst was considered in NIH-2 but not in the NIH-1 model. The nonideal homogeneous model NIH-1 was the best model to describe the kinetics of the transesterification reaction, and the accuracy of the reaction kinetic model is not improved by considering the effects of catalyst on the activities of the reactants and products.