Abstract: There have been a lot of published papers and patents since chloroaluminate ionic liquid was found to be a new kind of alkylation catalyst with high reactivity and easy seperation from reactants. However，There still are many difficulties and challenges to be overcome before commerical application of the ionic liquid catalyst. Based on the published data and several results of pilot alkylation，including the authors’ experience，the prospect of chloroaluminate ionic liquids used as alkylation catalyst in the petrochemical and detergent industries was discussed.