SiC whiskers were synthesized in a coke bed using a two-step heat treatment process. The temperature was held for 3 h at 1 200 ℃ before heating to 1 430 ℃ and holding for 3 h. The morphologies of SiC synthesized by the two-step heat treatment method were much more different from those produced by direct heating to 1 430 ℃. SiC whiskers formed at 1 200 ℃ firstly and grew at  1 430 ℃ to obtain a mean diameter about 326 nm, while the SiC grains with a size range from 0.70 to 2.30 μm were obtained by direct heating to the target temperature of 1 430 ℃. This was explained by the different formation mechanisms. The result proposes a promising alternative technical process for whisker-reinforced ceramic/refractory composites in-situ during sintering.