The interfacial reactions of B 4 C-coated and C-coated SiC fiber reinforced Ti–43Al–9V composites were investigated by scanning electron microscope and transmission electron microscope. The detailed microstructures as well as the chemical composition throughout the reaction zone were identified. For SiC f /B 4 C/TiAl composite, the reaction zone from B 4 C coating to TiAl matrix is composed of 4 layers, namely, a carbon-rich layer, a mixed layer of TiB 2 + amorphous carbon, a TiC layer and a mixed layer of TiB + Ti 2 AlC. For SiC f /C/TiAl composite, the reaction zone from C coating to TiAl matrix is composed of 3 layers, namely, a fine-grained TiC layer, a coarse-grained TiC layer and a thick Ti 2 AlC layer. For both kinds of composites, the reaction mechanisms of the interfacial reactions were analyzed, and the corresponding reaction kinetics were calculated. The activation energies of interfacial reaction in SiC f /B 4 C/TiAl composite and SiC f /B 4 C/TiAl composite are 308.1 kJ/mol and 230.7 kJ/mol, respectively.