Abstract: Fe-based amorphous alloy composite coatings were deposited on Q235 steel substrates via laser cladding. The influence of laser power on coating morphology, dilution rate, phase composition, microstructure, thermal stability, and mechanical response was systematically characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), differential scanning caborimetry (DSC), and Vickers microhardness testing. In the results, the coatings predominantly consist of α-Fe, Cr/Mo-enriched carbide/boride precipitates, and amorphous matrix. Laser power markedly affects both the dilution and the amorphous-phase retention. At 1200 W as the optimal laser power, the amorphous content (mass fraction) is 24.04%, the crystallization onset temperature is 732 K, and the amorphous formation capability parameter (a) is 0.618, indicating the superior thermal stability. The maximum microhardness reaches HV 1480 in the central region of coatings, roughly ninefold that of the Q235 substrates, attributed to the synergistic grain refinement and the homogeneous dispersion of strengthening precipitates.