This paper aims to study the friction and wear behavior of Al2O3 coating with atmospheric plasma spraying under high hardness. The Al2O3 coating was prepared by atmospheric plasma spraying (APS) with a thickness of 380 μm. Besides, the phase structure and morphology of the powder and as-sprayed coating were characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM). The X-ray energy dispersive spectrometer (EDS) was employed to analyze the transfer of grinding crack elements, while Al2O3 coating and two kinds of hardness and elastic modulus of friction pair were measured with the help of the nano indentation apparatus. In addition, the friction and wear behavior of the coating was systematically studied by the CSM friction machine. The chemical composition of the wear marks was analyzed by X-ray photoelectron spectroscopy (XPS). The Al2O3 coating was mainly composed of γ-Al2O3 phase, with a large number of pores and layered structure. In the friction experiment, it is found that under the same friction pair, the friction coefficient of Al2O3 coating decreased gradually with the increase of load, and the wear rate increased. Due to the differences in mechanical properties of friction pairs, Al2O3 coatings exhibited different frictional wear behaviors. When the friction pair was Si3N4, the friction coefficient of Al2O3 coating was small, but the wear rate was large. The friction mechanism was mainly abrasive wear and adhesive wear. At the same time, Si3N4 reacted with water in the air to form Si(OH)4 colloid with lubricating effect during the friction process. When the friction pair was WC, the friction coefficient was large, but the wear rate was low. The friction mechanism was mainly adhesive wear and abrasive wear, accompanied by fatigue wear. The γ-Al2O3 phase inversion occurred in Al2O3 coating on the surface of wear trace due to friction heat. The higher the friction coefficient was, the greater the hardness and elastic modulus of the friction pair was, and the more serious the γ-Al2O3 phase inversion was. The high hardness of Si3N4 and WC dual spheres has a significant effect on the friction and wear mechanism of Al2O3 coating prepared by atmospheric plasma spraying, and the γ-Al2O3 in the wear marks will change to α-Al2O3 during the friction process.