The diffusion brazing of TiC – Al 2 O 3 ceramic composite with W18Cr4V tool steel is realized by using Ti and Cu filler metals at 1500°K for 1 h under a pressure of 15 MPa in a vacuum of 10 – 5 Pa. Thus, a brazed TiC – Al 2 O 3 / W18Cr4V joint was obtained with an interface shear strength of up to 105 MPa. The microstructural characteristics of the TiC – Al 2 O 3 / W18Cr4V joint are studied by using a scanning electron microscope (SEM) with energy-dispersion spectroscopy (EDS) and X-ray diffractometer (XRD). The results indicated that the interface layer with a thickness of 90 μm was formed between TiC – Al2 O3 and W18Cr4V steel. The Ti and Cu filler metals were completely fused and diffused to react with Al and C from the substrates, whereas Ti 3 Al, Ti 3 AlC 2 , Ti C, and Cu Ti 2 were produced in the TiC – Al 2 O 3 / W18Cr4V joint. The TiC – Al 2 O 3 ceramic composite has high hardness and chemical stability and excellent wear resistance at elevated temperatures. Thus, it is extensively used as a cutting-tool and high-temperature structural material. It is not comparable with the other materials in high-speed cutting and for difficultly machined materials [1–3]. However, the brittleness observed after long-term operation exhibits a significant effect on its life. Thus, much attention is given to the investigation of joining of the ceramic composite with metals by using brazing processes. The results indicate that it is necessary to use some costly and high-temperature brazing filler metals, such as gold, platinum, and nickel for brazing in air to get perfect joints [4, 5]. With the development of vacuum techniques, the procedure of diffusion brazing in vacuum has increasingly progressed. It is now extensively applied in joining dissimilar materials and brittle materials, such as ceramics, intermetallics, hard alloys, etc [6 – 8]. If the procedure of joining of the TiC – Al2 O3 ceramic composite with tool steel can be realized in a vacuum and the joints obtained as a result have excellent performance, then we would get a new way to broaden the applications of the TiC – Al 2 O 3 ceramic composite in the machine-building industry.