in the exhaust reaction tube, the carbon fiber is heated to 1300-1500 ℃ by electric heating or infrared ray, and cyanoacetylene is introduced to deposit it on the surface of the carbon fiber to form a graphite layer, thus making carbon fiber as the core material and graphite as the outer layer of fiber with a diameter of about 100 μm, and then heating to 2000-3000 ℃ under inert gas in an electric furnace to graphitize to obtain graphite conductive fiber. The conductivity of graphite fiber fired at 3250 ℃ is 1.8 × 10 S/cm. When it is placed in air, the conductivity decreases at first, but it has remained at the level of 10 S/cm since then.