Abstract: The development of morphological structure and change of mechanical properities of Polyacrylonitrile oxidized fiber were systematitally characterized in the continuous carbonization process by means of TG, density measurement,gas chromatography,WAXD, AES-SIMS, metal-lograph,SEM as well as mechanical testing.The effects of different ways on improving the properties of resulting carbon fibers were presented and compared on experimental basis.Results show the intimate relation between rearrangement of structural features and revolution of mechanical Propertics.The extent of perfection is morphological structure and uniformity of cross-seetion surface of PAN oxidized fiber exnibit a great inflaence on final carbon fiber properties.