In this study, a mesoporous TiO2/carbon catalyst (TiO2/C) was prepared by a facile impregnation-carbonization approach to catalyze ozonation of p-chloronitrobenzene (p-CNB). The catalyst was well characterized and the catalytic efficiency under various conditions was systematically evaluated. TiO2/C has a disordered mesostructure with a high specific surface area. 92.8% of p-CNB (2 μmol/L) can be degraded within 20 min in the TiO2/C/O3 system in the presence of 1 mg/L O3, 100 mg/L catalyst, at pH = 5. Based on the evaluation of the effect of basic parameters, it could be deduced that the removal of p-CNB relied on the synthetic effect of catalysis by TiO2/C and the autocatalytic induction of p-CNB. The removal efficiency of p-CNB, the structure change and the leaching of Ti ions were also evaluated in five cycles, indicating TiO2/C is stable and recyclable for catalytic ozonation in water treatment.