Abstract: A new technology for manufacturing ultrafine WC-Co composite powder by reduction and carburization in fluid-bed has been described in this paper. It was shown by XRD analysis that the powder manufactured is composed of two phases of WC and Co. The average particle size of the powder determined by X-ray small angle diffraction testing was 0. 12μm. Teding bar with a theoretical density of 99. 7% was obtained by sintering such compacted powder sample in vacuum at 1280℃ for 1h.