Abstract: The active filler containing TiZrNiCu was used to join TiB_w/TC4 alloy and C/C composite. The effect of the brazing parameters on the interfacial microstructure was studied by SEM, EDS, and XRD. The results show that the typical interfacial structure of the joint is C/C composites/TiC +(Ti,Zr)₂(Cu,Ni)/Ti(s,s) +(Ti, Zr)₂(Cu, Ni)/TiB_w/TC4 alloy. With the increasing of brazing temperature or holding time, the type of the interfacial products in the brazing joint did not change, but the reaction layer of TiC near the C/C composites became continuous and thickness gradually increased, α-Ti dendrites became thicker and the number increased. The layer of Ti(s, s) +(Ti, Zr)₂(Cu, Ni) became wider, the phase(Ti, Zr)₂(Cu, Ni) gradually dispersed in Ti(s,s).