VC (Vanadium Carbide) coating was prepared on the substrate surface of Cr12MoV from the raw materials such as anhydrous borate, FeV50, FeSi45 and etc. by TD (Thermal Diffusion) process, the coating structures and chemical element contributions were characterized with SEM (Scanning Electron Microscope), XRD (X-ray Diffraction), XPS (X-ray Photoelectron Spectroscopy) and EDS (Energy Dispersive Spectrometer), respectively. The chemical element distributions of VC coating surface and interface was analyzed with plane scan of energy-dispersive spectroscopy, and the mechanism of interfacial metallurgical combine was discussed. The results show that VC coating is a compound, consisted of C and V elements, and the V atom concentration is twice as that of atom; VC coating is the single VC phase, the electron binding energy of V element is located at 512.8eV, and that of C element is located at 282.2eV; There were diffused between V, C and Fe elements each other in the coating interface, forming a interface diffusion layer, the interface of VC coating-substrate is combined with the metallurgical combine.