Abstract: A new catalyst,namely SO42-/TiO2 solid superacid, used in the synthesis of perillartine from α-pinene by three-step process, has been screened, and the preparation conditions of the catalyst were:concentration of sulphuric-acid 0.5 mol/L, calcination temperature of the catalyst 300℃, calcination time 3h.The catalyst has been used to catalyze isomerization of myrtenal to produce perillaldehyde, and the optimal process parameters were as below:reaction temperature 400℃, reaction pressure 28 kPa, air speed 12h-1.the maximum conversion of myrtenal was 87.45%, the yield of perillaldehyde was 41.29%, the three-step reaction overall conversion was 33.49%.Physical properties of the catalyst were investigated with IR, TPD and BET in terms of their catalytic capability.The experimental results showed that chelated surface of SO42-/TiO2 solid superacid was formed, and the catalytic activity was increased with increase of specific surface area and total acid content.