The invention relates to a method for an alkylation reaction of isobutane and butylene and a system. The method for the alkylation reaction of the isobutane and the butylene comprises the steps of enabling a raw material containing the isobutane, n-butane and butylene to enter a reacting section in a manner of being divided into multiple feed material flows, subjecting the isobutane and the butylene to a reaction in the presence of a catalyst so as to produce C8 alkane, subjecting unreacted isobutane and butane to separation, mixing the separated isobutane and butane with the raw material, and enabling the raw material to enter a reacting section. According to the method and the system, the butylene can be thoroughly diluted in the reacting section, the possibility of polymerization of the butylene is reduced, the speed of catalyst activity lowering is lowered, meanwhile, the recycle ratio of the isobutane is lowered, and the energy consumption is lowered.