Rod-like α-sialon was synthesized successfully using pure SiO2 and AlN as the starting materials, carbon black as reductant, CaF2 and Y2O3 as addition agent by carbothermal reduction-nitridation. The effects of reaction temperature (1450°C, 1500°C, 1600°C and 1700°C) and additive (Li2CO3, CaF2, Y2O3 and Y2O3+CaF2) on phases and microstructure of the final products were studied by XRD and SEM. The results showed that α-sialon was synthesized by carbothermal reduction-nitridation at 1700°C for 3 hours. The morphology of the synthesized α-sialon was rod-like.