Utilizing petroleum coke as fuel in an efficient and environmentally friendly way is a great challenge. Within the technological framework of chemical looping combustion, the reaction of the oxygen carrier CuFe2O4 with a typical high-sulfur petroleum coke (designated as JS) was performed, focusing on the conversion of the JS coke, the oxygen transfer from CuFe2O4, and the reaction characteristics involved. Simultaneously, the evolution of sulfur and minerals present in JS was also considered. Thermogravimetric analysis of the reaction of CuFe2O4 with JS demonstrated the reaction superiority of CuFe2O4, with its reactivity being close to that of CuO. The preferred CuFe2O4 oxygen excess number phi for JS conversion was determined as unity. Furthermore, both the experimental means, including Fourier transform infrared spectroscopy, field scanning electron microscopy/energy-dispersive X-ray spectrometry and X-ray diffraction analysis, and the thermodynamic simulation of the reaction of CuFe2O4 with JS indicated that the main reduced counterparts of CuFe2O4 were Cu and Fe3O4. Most of the organic sulfur dominant in JS coke reacted with the reduced CuFe2O4 to form Cu2S, and the side product Fe2SiO4 should also be noted for its detrimental effect on the reactivity of CuFe2O4.