The treatment of industrial wastewater with various organic compounds was essential for the source control of water pollution. Catalytic ozonation process was widely used in wastewater treatment due to its higher efficiency and easy operation. In this work, Ca 2 Fe 2 O 5 was prepared by the sol−gel method and used as a catalyst to remove quinoline effectively by the catalytic ozonation process. The physical and chemical properties of the catalyst have been well characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N 2 physical adsorption−desorption profiles, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results have shown that calcium iron oxide has sheet micromorphology and good crystal structure. In addition, the Ca 2 Fe 2 O 5 catalyst has more oxygen vacancies than the Fe 2 O 3 catalyst, which can promote the decomposition of ozone molecules to produce active free radicals effectively. In this study, the Ca 2 Fe 2 O 5 catalyst has shown higher catalytic activity than the other reported catalysts, which can remove quinoline and other organics from an aqueous solution effectively. In the Ca 2 Fe 2 O 5 /O 3 system, more ozone molecules decomposed to generate • OH radicals, which inhibited the direct reaction of ozone and quinoline to produce NH 4 + -N. Meanwhile, • OH radicals generated in the catalytic ozonation process has increased the chemical oxygen demand removal rate efficiently. In addition, the intermediate products in the catalytic ozonation process were studied by electrospray ionization−mass spectrometry analysis. This research shows a promising way to prepare efficient catalysts for the treatment of quinoline by the catalytic ozonation process.