The work aims to investigate the effect laws of scanning speed on the degree of cutter substrate thermal influence, the heat accumulated warping deformation and microstructure of substrate, and the phase composition of cladding layer during laser cladding of thin plate W6Mo5Cr4V2 high-speed steel and then find the appropriate parameter selection range of speed scanning for thinner high-speed steel cutter. A series of single-pass cladding layers were prepared by single control variables. The influence characteristics of different scanning speed on the morphology of thermal influence, the deformation of structure, the microstructure and the microhardness of substrate were analyzed. With the increase of scanning speed, the heat-affected zone decreased, the heat accumulation increased gradually along the cladding direction, and the area of the heat-affected zone spread to both sides along the cladding direction. When the scanning speed was 2 mm/s, the deformation of the substrate bottom was 0.077 mm, the deformation expanded from the center to the edge and the central part corresponding to the cladding path was the most prominent. When the scanning speed was above 3 mm/s, the deformation was reduced to within 0.03 mm. When the scanning speed was 4 mm/s, the maximum crack width between the cladding layer and the left and right boundaries of the substrate was reduced to 0.013 mm, and the crack length was significantly reduced. Different scanning speed only affected the microstructure refinement degree and the maximum microhardness range of the cladding layer, but had no significant influence on the strengthening mechanism and phase composition of the cladding layer. During the laser cladding of thin plate high-speed steel cutter material, faster scanning speed can reduce thermal influence degree on the surface of the substrate material, but slow scanning speed is easy to cause the "saddle" warping deformation of substrate. When scanning speed is more than 3 mm/s, the warping deformation of the substrate can be effectively controlled within 0.03 mm and the size of crack on combined boundary can be effectively reduced by increasing the scanning speed.