This paper presents a process for the fabrication of particle-reinforced Ti/B4C/dr40 composite coatings on the surface of shaft parts by laser cladding technology. The mechanism of in situ ceramic particle and its refinement of the grains during the solidification process, the transformation from columnar to equiaxed crystals, the generation of cracks on the composite coating surface, and the effect of the temperature gradient and solidification rate on the microstructure were investigated and analyzed. In order to analyze the mechanical properties of the composite coating, indentation and scratch tests were carried out. The results show that the composite coating exhibits good metallurgical bonding with the substrate and the TiC and TiB2 hard particles generated during the solidification process play a skeletal role during wear process, inhibiting the plastic deformation of the matrix, reducing the material removal, and improving the microhardness and wear resistance of the composite coating. The research indicates that the fabricated Ni-based composite coatings by laser cladding technology can be used to achieve surface strengthening and remanufacturing of shaft parts.