SO2-4/TiO2-La2O3, a novel solid superacid,was prepared and its catalytic activities at different synthetic conditions were analyzed with esterification of n-butanoic acid and n-butyl alcohol as probing reaction. The optimum conditions were as follow: mole ratio of n(La3+)∶n(Ti4+) of 1∶34, the soaked consistency of H2SO4 of 0.8mol?L-1, the soaked time of H2SO4 of 24h, the calcining temperature of 480℃, the calcining time of 3h. The catalyzer prepared under the optimal conditions was applied in the catalytic synthesis of ten important ketals and acetals as catalyst and exhibited high catalytic activity. The yields of ketals and acetals can reach 41.4%~95.8% when the molar ratio of aldehyde/ketone to glycol is 1∶1.5, the mass ratio of the catalyst used in the reactants is 0.5%, and the reaction time is 1.0h.