Rutile and fly ash powders were nitridized at different temperatures for 4 h. The influence of temperature on phase composition of nitridation products from rutile and fly ash was studied. XRD, SEM and EDS analyses show that: the phase compositions of the products was quite dependent on the reaction temperature. Mullite, O'-Sialon and X-Sialon were formed from 1400 °C to 1450 °C. Rising temperature would get Mullite nitrided. Meanwhile, O'-Sialon and X-Sialon would be nitrided and transformed into β-Sialon. At temperatures above 1550 °C, the main phases of the products were hexagonal columnar β-Sialon and irregular TiC0.3N0.7 grains.