The effect of B 4 C particle size on the reaction behavior of TiC–TiB 2 ceramic/Cu composites from a 40wt.% Cu–Ti–B 4 C system by self-propagation high-temperature synthesis (SHS) was investigated. It was found that increasing B 4 C particle size not only makes the ignition and self-sustainment of the SHS reaction difficult but also decreases the combustion temperature and combustion wave velocity. The reaction products are dependent on the B 4 C particle size. Favorable composites consisting of TiC, TiB 2 and Cu phases could be obtained by the control of B 4 C particle size. The reaction path was explored through a delicate microstructure and phase analysis on the combustion-wave quenching method. From the reaction path, the effect of B 4 C particle size on the ignition behavior, combustion characteristics and products of the Cu–Ti–B 4 C system can be clearly clarified.