In this paper, the effect of B₄C content and heat treatment temperature on microstructure, mechanical properties and oxide resistance of SiC refractory ceramics were investigated. The results show that the inclusion of B₄C could improve the crystallinity of gengerated SiC and graphitization. When the B₄C content was 6%, the linear change of SiC-based refractory ceramics after heat treatment at 1450°C decreased from 1.39% to 0.58%. At the same time, the cold modulus of rupture and cold compressive strength increased by 1.8 times and 2 times, respectively. Meanwhile, with the increase of B₄C content, the oxidation index of the SiC-based refractory ceramics decreased from 30.33% to 16.63% after oxidation at 1400°C.