Abstract: Established numerical simulation model of preset style powder layer for laser reaction cladding based on ANSYS softwear, considering the effect of latent heat of phase change, radiation and convection heat dissipation and surface effect units, etc. The laser reaction cladding temperature field of carbide ceramics coating was calculated by the model under different processing parameters, and the changes of temperature field during the laser process was analyzed. The results show that laser power and scanning rate had more significant effect on the melt thickness of the substrate and the cladding layer width, and the laser power was the main effect factcr to cause fairly high temperature gradient in cladding layer. The optimal process parameters obtained from finite element simulation was validated by test.