The brazing parameters and microstructure in the interface of WC-TiC-Co hard alloy and the brazing filler were investigated by means of inside-furnace brazing, scanning electron microscopy (SEM) and X-ray diffraction. Test results indicated that the brazing joint with which the interface combines excellently can be obtained by using Cu-Zn-Ni brazing filler alloy and controlling the heating temperature 940-960℃, the heat preservation time 10-15min and a suitable cooling. The crystal microstructure of the brazing filler alloy is α+β eutectic. The interface microstructure of the hard alloy and the brazing filler alloy distribute evenly. The interface zone consists of WC, TiC, CuZn (s-phase). There are no microcracks, inclusions, etc. nearby the interface. The interface zone is formed by mutual diffusion of the hard alloy and the brazing filler alloy under high temperature.