Palygorskite（PGS）supported TiO2 is prepared by dipping method of acid activated palygorskite, and then it is modified by H2SO4 to achieve the SO42- / TiO2-PGS solid super acid. The catalyst is characterized by FT-IR, XRD spectroscopy, SEM and BET. It is applied in trioctyl trimellitate synthesis．The orthogonal experiment shows that the esterification yield is 94.15% under the conditions： the molar ratio of trimellitic anhydride to 2-ethylhexyl alcohol is 1∶4.5, the weight of catalyst is 3.7％of total weight, the reaction time is 6 h and the oil bath temperature is at 210℃．