In this work, magnesia from natural brucite mineral has been used firstly for catalytic degradation of nitrobenzene and aniline in presence of ozone. Compared with single ozonation, the catalytic ozonation accelerated markedly the degradation of nitrobenzene and aniline. The influences of hydroxyl radical scavengers, pH values, and reaction temperatures on degradation were investigated. It was found that the essential of catalysis was the homogeneous catalysis of hydroxyl ions in water, which accelerated the generation of hydroxyl radicals. As a catalyst, magnesia from natural brucite has supplied an economical and feasible choice for catalytic ozonation of nitrobenzene and aniline in industrial wastewater.