We design and synthesize 1-(methoxyethyl)-3-methylimidazolium hydrogen sulfate ionic liquid ([MOE-MIM]HSO4). The ionic liquid is characterized by thermogravimetric analysis, HNMR, (CNMR)-C-13, and FTIR spectrum. The synthesis of butyl acetate is based on an orthogonal array experimental design (OA9 matrix). A high conversion rate of acetic acid of 97.72 % is obtained under optimal reaction conditions. In addition, [MOE-MIM]HSO4 exhibits low solubility in butanol and is immiscible with butyl acetate, thereby making it easily separated from the products. After reuse for five cycles, the catalytic activity of [MOE-MIM]HSO4 is nearly unchanged.