Abstract: A kind of Keggin structural 12-WP acid was prepared and used as catalyst to synthesize methyl tertbutyl ether (MTBE) from methanol and tertbutanol. The influences of the amount of 12-WP acid, the ratio of reactants and reaction temperature on the yield of MTBE were investigated. The results showed that the conversion of tertbutanol, selectivity of MTBE and the yield of MTBE could be up to 59.6%，74.5% and 44.4%, respectively when the amount of 12-WP acid was 2.16% of tertbutanol and the mole ratio of tertbutanol to methanol was 1∶1.2 at 100℃.