Chromium aluminum oxynitride (Cr-Al-N-O) films have been successfully prepared by pulsed laser deposition (PLD). Experiments were carried out by changing the surface area ratio of the target [SR = S-AlN/(S-Cr2N+S-AlN)] under a pressure of 1 x 10(-5) torr. The composition of the film prepared at fluence of F = 5 J/cm(2) and Si-R = 75% was determined to be Cr0.11Al0.39N0.25O0.25 by Rutherford backscattering spectroscopy (RBS). The oxidation of the Cr-Al-N-O film was observed above 900 degreesC. Additionally, the film heat-treated at 1100 degreesC consisted mainly of B1 (NaCl) structure. From the result of grazing angle X-ray difftactometry (GXRD), the oxidation resistant of Cr-Al-N-O film was found to be improved due to the fact that Cr2O3 and alpha-Al2O3 is formed near the film surface.