Applied solid superacid SO42-/SnO2 to catalyze α-pinene Isomerization, which was prepared by the azeotropic dechlorination method. The optimum conditions for these catalyst preparation were that impregnated with 1.5 mol/L H2SO4, calcinated at 550 ℃ for 3.0 h; The optimal reaction condition for reacted at 110 ℃ for 3.0 h, the mass fraction of catalyst was 5%(relative to the weight of α-pinene in turpentine); Under these conditions, the conversion of α-pinene was 100%, and the selectivity of camphene was 64.85%. These catalyst were characterized by FT-IR, XRD, TG-DTA, SEM and BET. Results showed that catalytic activity of SO42-/SnO2 which was prepared by the azeotropic dechlorination method higher than Sol-gel and precipitation method in the same preparation conditions, prepared by the azeotropic dechlorination method’s SO42-/SnO2 had more super acid, smaller, uniform particles and less reunion than Sol-gel and precipitation method’s SO42-/SnO2.