Abstract: The oxidation of the self lift-off silicon microchannels is studied. Self lift-off silicon microchannels are fabricated by a new technology: under certain experimental conditions, the silicon microchannels can lift off from the substrate automatically after electrochemical etching. In the process of the traditional dry-wet-dry oxidation, damages and distortion of the silicon microchannels occurred. It was found that the thinner the silicon microchannels, the more serious the distortion and damages are. By using thicker silicon microchannels and adding a procedure of dry oxidation before the dry-wet-dry oxidation, the damages and distortion of the silicon microchannels can be eliminated.