Abstract: Sm₂O₃-SmF₃ binary sintering aids were used to investigate the influence of different sintering aid content ratios on the densification degree, phase composition, microstructure, thermal properties, and mechanical properties of Al N ceramics in this study. By combining the advantages of rare earth oxides and fluorides, which strengthen grain boundaries while purifying the lattice, high-performance Al N ceramics were ultimately prepared. The results show that aluminum nitride ceramics with excellent performance are prepared by pressureless sintering with 1850 ℃ in a nitrogen atmosphere for 4 h.Samples with Sm₂O₃ and SmF₃ content of 3wt% and 2wt% respectively, have the best comprehensive performance, with a thermal conductivity of 185.7 W/（m·K） and an average bending strength exceeding 400 MPa.