The Friedel-Crafts alkylation of naphthalene with 1-octene was completed using methanesulfonic acid (MSA) as catalyst and 2,6-di-t-butylphenol as polymerization inhibitor. Single factor experiments were carried out to investigate the influence of the molar ratio of naphthalene to 1-octene, the amount of MSA, reaction temperature and reaction time on the olefin conversion and the yield of product in order to obtain the optimal reaction conditions. The experimental results show that after the reaction conduct for 3h at 353K, the olefin conversion of 95.2% and the yield of product of 78.4% are obtained with the molar ratio of naphthalene to 1-octene of 1.3 and the molar ratio of MSA to 1-octene of 1.0. Under the optimum conditions, the lubricating base oil is synthesized and its physical, chemical and electrical properties are determined. The results suggest that the synthetic base oil could be used as a component for transformer oil.