The multiphase composite and the computer aided design of the ceramics are two significant trends in the development of the advanced ceramic materials in the 21st century. Mathematical models have been built for the description of the relationships between the mechanical properties and the material compositions of the multiphase composite ceramic tool material with the combination of both theoretical and experimental methods. The optimum compositions of the material have also been achieved by means of the computer aided optimization technology. Then, an advanced Al₂〇₃—SiC-(W,Ti)C multiphase composite ceramic cutting tool material is fabricated with hot pressing technology. The material is found to possess high comprehensive mechanical properties, which proves that the method proposed in the present study is reasonable and feasible for the design of multiphase composite ceramic tool materials.