A series of acidic ether functionalized chloroaluminate ionic liquids were synthesized and studied. The catalyst with the highest acidity was screened out by FT-IR spectra using acetonitrile as infrared probe and used to catalyze the alkylation of isobutane with 2-butene. It was proved that the acidity of 1-methoxyethyl-3- methylimidazolium bromide aluminium chloride ([MOEMIM]Br/AlCl3) was the highest when the molar ratio of AlCl3 was 0.75. The high quality alkylate with a C8 selectivity of 66.6%(mass) was obtained at 35℃ with the isoparaffin/olefin molar ratio (I/O) of 10

which was much better than that with non-ether functionalized chloroaluminate ionic liquids. The catalysts could be reused several times without obvious loss of activity.