WC-Co cemented carbide has been widely used as cutting tool materials under cooling conditions. However, WC-Co cemented carbide has low high temperature hardness and poor oxidation resistance at high temperature, which limits its application in the field of high-speed machining. New WC-Al₂O₃ composite tool materials with high hardness and excellent oxidation resistance at high temperature were fabricated by vacuum hot pressing sintering process at 1450 °C. The mechanical properties of WC-Al₂O₃ composite tool materials with different Al₂O₃ content were studied at room and high temperature, combined with the microstructure analysis by XRD\SEM\EDS. It was found that WA5 (5 wt.% Al₂O₃) had the best comprehensive mechanical properties at room temperature, but its performance at high temperature was inferior to WA20 (20 wt.% Al₂O₃). The Vickers hardness of WA20 was 21.3 \(\pm \) 0.19 GPa at 600 °C, which was higher than WA0 (3.44 \(\pm \) 0.24 GPa) and WA5 (4.4 \(\pm \) 0.08 GPa) at 600 °C. The oxidation experiment showed that the weight gain of WA20 at high temperature (700 °C and above) was significantly lower than that of WA0 (0 wt.% Al₂O₃) and WA5, which was due to the good high temperature oxidation resistance of Al₂O₃. In general, WA20 had good high temperature mechanical properties and better high temperature oxidation resistance, which was suitable for high-speed cutting tool.