This paper presented the results of catalytic ozonation of phenol over nanosized Mn O_2 supported on reduced grapheme oxide,and the influencing factors and mechanism of pollutant degradation by catalytic oxidation was primarily explored. The nanocomposite was well characterized by SEM,TEM and XPS. The pseudo first order reaction was used to represent the process of catalytic ozonation; the optimal catalyst usage was 0. 2 g / L; the removal efficiency of phenol by catalytic ozonation was improved by 119. 0% ...