Ti-Ni-Mo-Si composite coating was fabricated on mild steel by reactive braze coating process with Ti61.9Ni24.6Si4.4Mo9.1 ( wt.％ ) powders as the raw materials.Microstructure of the coating was characterized by optical microscopy,scanning electron microscopy,X-ray diffraction and energy dispersive spectroscopy and micro-hardness tester.Results indicate that the Ti-Ni-Mo-Si composite coating is metallurgically bonded to the mild steel substrate and has high hardness. The microstructure of the coating consists of the reinforcement of Ti5 Si3 and Mo9 Ti4 particles and the matrix of eutectic NiTi2.Due to the poor wettability of NiTi2 liquid at low temperature,Ti5Si3 and Mo9 Ti4 do not uniformly distribute in the NiTi2 matrix.