TiCx/Cu composites were fabricated by combustion synthesis and hot press technology. Using XRD, SEM, EDS, FESEM analysis methods, the effects of various carbon sources and different Cu contents on the microstructures of TiCx/Cu composites and the size of TiCx particles were investigated. Results showed that TiCx reinforcing particles size increases with decreasing Cu content in Cu-Ti-C reaction system. With carbon nanotubes (carbon black) serving as carbon source, the generated TiCx particles size transits from nanometer to submicron when Cu content corresponding to the reaction system is reduced to 60 vol％ (70 vol％); while graphite serves as carbon source, there is no clear limiting concentration. C particles with smaller size, larger specific surface area and better distribution result in finer TiCx particles, which is more beneficial to generating nano-sized TiCx/Cu composites.