Abstract: The Ag-Cu-Ti filler metal was wetted on C/C composites by the TIG arc directly. The macroscopic features of the wetting filler metal under different holding times were observed. Besides, the microstructure and element distribution of the joints was analyzed by SEM and EDS, respectively. The experimental results showed that the filler metal can soften under certain holding time. When the holding time was 60 min, the wetting effect of filler metal on C/C composites was the best. The distribution of the TiC reaction layer was the most uniform and dense with a thickness of 1.3 μm. Besides, the maximum thickness of the diffusion layer was 5.5 μm. When the content of copper and silver in the filler metal approaching to the reaction interface remained the same, there were brittle compounds such as AgTi/CuTi₃/Cu₄Ti₃. Meanwhile, Ti elements gathered near the interface and Ti₂Cu was produced in the aggregation area.