AgCuTi-based composite fillers reinforced with Carbon Nanotubes (CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD) and a Differential Scanning Calorimeter (DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy (TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system. The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure. Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu2 with high Ti content and Ti2Cu3 phases to TiCu4 phase with low Ti content. Additionally, the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs. Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.