The work aims to explore the influence of oxygen flows on structure and properties of arc ion Plating TiAlON coatings. TiAlON coatings of different oxygen content were deposited on high-speed steel at varying oxygen flows by the self-produced arc ion plating system. The components of the coatings were analyzed with EDS in combination with XPS. The crystal structure of the coatings was analyzed with XRD. The surface morphologies of the coatings were analyzed with SEM. The hardness of the coatings was characterized with Knoop hardness; and adhesion strength of the coatings was analyzed with indentation method and scratch method. The surface morphologies and components of the coatings after heat treatment after being kept at 900 ℃ for one hour were analyzed. The results showed that the O content incorporated into the coatings varied from 57.48at.% to 62.32at.% with the oxygen flow increasing from 30 mL/min to 120 mL/min. The N element incorporated into the coating was little (less 1.51at.%) and is dominated by (200) crystal face orientation. As the oxygen flow increased, the size and number of droplets and holes on the coating surface increased first and then decreased. The hardness and adhesion strength of coating changed in a small range. Spalling areas, bulges and outward-diffused substrate elements were found on the coating surface with oxygen content less than 60.55at.% after the high temperature oxidation test. When the oxygen content increased to 61.20at.%, spalling areas and bulges were not found on the coating surface. Oxygen flow is positively related to the high temperature oxidation resistance of TiAlON coatings. The increase of oxygen flow changes the arc discharge state, which has great influence on the surface quality. The hardness and adhesion strength of the coating are not affected by oxygen flow.