Abstract: Plasma welding technology was used to melt the Fe-Cr-Ti-C system wear-resistant alloy on the low-carbon steel, TiC and M₇C₃ were in situ synthesized in the surfacing layer, and the formation mechanism of TiC and M₇C₃ ceramic hard phase in the weld pool was studied.X-ray diffraction(XRD), scanning electron microscope(SEM), spectrum analyzer(EDS) were used to test the microstructure of the surfacing layer.The result shows that a large number of cross flower-shaped, short rod-shaped, granular TiC ceramic hard phase and hexagonal rod-shaped M₇C₃ ceramic hard phase are formed in the surfacing layer.Part of the TiC and M₇C₃ ceramic hard phase work closely together and the bonding strength between the ceramic hard phase of TiC and matrix structure is improved.The M₇C₃ grains could form next to the TiC ceramic hard phase, and formation of TiC hard phase improves the nucleation rate of M₇C₃ hard phase.