The surface oxidation of CrN thin films prepared by the cathode arc ion plating method was studied by X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) using soft X-rays from synchrotron radiation. The results indicate that molecular nitrogen is formed in the interstitial position of the chromium oxide matrix at the initial stage of oxidation. On further oxidation, at a higher temperature, molecular nitrogen is gradually released from the surface, with part of the displaced nitrogen remaining in the interstitial position.