Multi-walled carbon nanotubes (MWCNTs) reinforced Si 2BC 3N ceramics were prepared through mechanical alloying (MA) and following spark plasma sintering (SPS). The thermal shock resistance of Si 2BC 3N ceramics was evaluated comparatively through ice water quenching test and theoretical prediction. Furthermore, the oxidation resistance of MWCNTs incorporated Si 2BC 3N ceramics was evaluated under high temperature. The results show that the calculated parameters such as the critical thermal shock temperature ( R) and the thermal stresses resistance ( R st), as well as the toughness ( R′′′′) are improved with addition of 1 vol% MWCNTs. In addition, the crack propagation resistance of 1 vol% MWCNTs incorporated Si 2BC 3N ceramics is obviously improved through generating more tortuous crack propagation paths attributing to the “crack bridging”, “pull-out”, and “crack deflection” mechanisms of MWCNTs. Therefore, the residual strengths of 1 vol% MWCNTs containing specimens remained the highest after the thermal shock tests. Besides, the present work also reveals that the oxidation resistance is more sensitive to relative density than MWCNTs addition.