A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF2 as sintering aid were prepared by spark plasma sintered at 1700-1850 ℃ for 5 min.The addition of CaF2 effectively lowered the sintering temperature and promoted the densification of AlN-BN composites.With the increase of sintering temperature,the density increased,and the contiguity of AIN grains enhanced in AIN-BN composites.Thermal conductivity of AIN-BN composites increased with the increase in CaF2 content and sintering temat 1800 ℃.