In order to resolve the present shortcomings of preoxidation such as preoxidation technology taking too much time, lower production and higher energy consumption for producing high performance carbon fiber, a new type of fluidized preoxidation technology and its effect on the oxidated fibers have been studied in detail. The fluidized fibers have been compared with preoxidized fibers made under conventional technology. It has been found that the technology succeed in the excellence of high efficiency of mass transfer, heat transfer and energy saving. The oxygen content of preoxidized fibers fluidized attained to 11.1%, and the density of 1.42 g/cm(3) of preoxidized fibers fluidized can be attained. It was founded that the fluidization-treated PAN fibers not only provide an increase in the tensile strength by about 17%, in the elongation at break by about 13%, and in the carbon yield by about 3%, but also provide a decrease in the tensile modulus by about 7%, and in the fineness by about 21%, when compared with the untreated PAN carbon fibers.