The invention belongs to the technical field of solid acid alkylation, and particularly discloses a method for catalyzing iso-butane and n-butene alkylation by solid acid. In the method, Nafion functional hydrophobic SBA-15 is adopted as a catalyst, iso-butane and n-butene is used as reactants, and continuous operation of a fixed bed reactor is adopted to realize the alkylation of the solid acid under the pressure condition of ensuring the reactants to be liquid at the temperature of between 30 and 110 DEG C. By using the catalyst, higher butene conversion rate and trimethylpentane (TMP) selectivity can be obtained.