In this study, a continuous stabilization process is used to make high-performance carbon fiber from polyacrylonitrile(PAN)-based fibers. The effect of oxygen content of PAN-based fibers on the stabilization process and the properties of the resultant carbon fibers is investigated. In order to research the progress of stabilization reaction, FT-IR, elemental analysis, density, DSC, etc are used.Stabilization is carried out in air atmosphere from the 200 to 300℃ temperature range.An increase of PAN-based fibers diameter reduces the oxygen content during the continuous stabilization process. A higher oxygen content increase the density, tensile strength and modulus in the resultant carbon fibers.The most appropriate oxygen content in the stabilized fiber should be about 12%. Fibers having more than 12% oxygen content yield carbon fibers with inferior properties. Those carbon fibers also have sufficient commercial availability.