The present invention pertains to a method for manufacturing alkylate oil using a composite ionic liquid as catalyst. A mixture of isobutane and C4 olefins is used as the raw material, and a composite ionic liquid is used as catalyst to carry out an alkylation reaction. The alkane/olefin ratio in the raw material is higher than 1:1. In the composition of the aforementioned composite ionic liquid catalyst, the cations come from a hydrohalide of an alkyl-containing amine or pyridine, while the anions are composite coordinate anions coming from two or more metal compounds. One of the metal compounds is an aluminum compound, while other metal compounds are compounds of Group IB and Group IIB elements of the Periodic Table and the transition metals. The present invention also provides a design of static mixer reaction apparatus that can realize the aforementioned manufacturing method. The method of the present invention increases the selectivity of the alkylation reaction to give the alkylation product a relatively high octane number and further increase the product yield. Also, the manufacturing operation is simplified, and the cost can be reduced. This method is an environmentally friendly method that will not pollute the environment.