The effects of sintering cycles and doping elements on the microstructures of Ln-alpha-sialon were studied. The results showed that microstructures with an elongated alpha-sialon morphology could be obtained through high-temperature post-heat treatment (1800-1900degreesC) or by prolonging soaking times during sintering. Different rare-earth elements had a profound effect on the microstructure of the resulting a-sialon. The Ln-alpha-sialon doped with low-Z-value elements could easily develop elongated grains with higher aspect ratio.