Three kinds of the sialon ceramics with and without TiN additions were prepared by hot pressing to investigate the effect of microstructure on erosion behaviors. Hardness and fracture toughness were measured with prepared specimens to study the effect of additives on the mechanical properties. A gas blast type erosion tester was employed to examine erosion behavior of the specimens up to $600^{circ}C$. Erosion tests showed an increase of erosion rate up to 40$0^{circ}C$ and a gradual decrease of erosion rate up to 50$0^{circ}C$ for all kinds of sialon. The results also showed that erosion rates of the sialons were controlled better by microstructural factors than by mechanical properties including fracture toughness and hardness.