The application of laser cladding technology in thin-wall repair is limited by the instability deformation of the substrate. This paper discussed the characteristics of the instability deformation mechanism, the phase composition change of the fusion area and the surface layer of the thin-wall, the microstructure and microhardness and other properties through the test of laser cladding 2 mm thin-plate. The results show that the thermal stress plays a decisive role in the buckling deformation of 08 steel plate after 316L laser cladding. The fusion zone of thin plate surface produces a planar crystal fusion zone of about 5 μm brightness, and the phase content and mechanical properties of the fusion zone are close to that of cladding alloy. A single grain coarsening zone of 30 μm is generated in the heat affected zone of thin plate matrix. Due to the uneven residual stress, the materials around the micro indentation appear uplift.