Silicon carbide whiskers were prepared by carbothermal reduction. Materials are silica fume and carbon black, Si, Fe2O3, Si-Fe as catalyst, the phase composition and microstructure of compound products were investigated by XRD and SEM, effect of synthesized temperature, kind of catalysts, amount of catalyst were discussed. The results showed that: Silicon carbide whiskers were synthesized by silica fume and black carbon, add catalyst, synthesis temperature is 1550°C. Synthesis effect of silicon carbide whiskers with Si is better than Si-Fe and Fe2O3. Adding amount of Si is 2%, synthesized rate of silicon carbide whiskers is high, it is straight, length is 10~15μm, diameter is 0.1~0.3μm.