To investigate the effect of laser remelting on the microstructure and properties of diamond/Ni-based composite coatings, diamond/Ni-based composite coatings were prepared on the surface of Q235 by induction heating. The macroscopic morphology, microstructure, elemental distribution and mechanical properties of the coatings before and after laser remelting were analyzed by ultra-deep field microscope, laser confocal microscope, scanning electron microscope, energy spectrometer, X-ray diffractometer, hardness tester and abrasive wear tester. The results show that after laser remelting, the number of exposed diamonds on the surface decreases and the average roughness of the surface of the composite coating decreases from 5.58 μm to 4.88 μm. The number of hole defects in the microstructure is significantly reduced, and the carbide in the microstructure aggregates and grows up, while the enrichment degree of Cr element increases around the diamond; there is no significant change in the microhardness of the brazing alloy and the abrasion-resistant properties of the coating.