The invention provides an alkylated gasoline preparation method based on an ionic liquid catalyst. The preparation method takes isobutane and butylene as raw materials and takes a mixture of ionic liquid LX and ionic liquid WZ as a catalyst to react for 10min to 30min under the conditions of 10 DEG C to 50 DEG C and 0.2Mpa to 1.5Mpa; a reaction product is layered and an upper-layer product is alkylated gasoline. The multi-sulfonic-group ionic liquid catalyst provided by the invention has the advantages of high acid density, small use amount of the catalyst, good repeatability, convenience for separating the reaction product, relatively simple preparation and use conditions, small basic corrosion on equipment, small basic hazard to environments and the like.