AlN/SiC composites have received considerable attention owing to their wide application for high thermal conductivity.AlN-0-30 wt.%-SiC composites with 5 wt.%Y2O3 addition were fabricated by pressureless sintering at temperature 1650-1950 ℃.The influences of sintering temperature and SiC content on the density,mechanical property and thermal conductivity were studied.