Abstract: The high-strength bonding between steel matrix and diamond grit was obtained by using Ag-Cu-Ti brazing filler metal in vacuum furnace.The microstructure on the interface between diamond and the filler metal and carbide which was formed on the diamond surface was observed with scanning electron microscope, and the change of components in it was analyzed with energy dispersion spectroscope and the structure of the diamond was analyzed with Raman.Results showed that Ti in Ag-Cu-Ti separated out at the interface to form lump-like TiC carbide on the surface of diamond, which was less than 1 μm in size.Meanwhile, the diamond wasn't graphitized in the high temperature.As a result, the serial of diamond-TiC-filler metal-steel matrix was formed between the interface of the diamond and the filler metal.