Surface on 2Cr13 stainless steel was cladded with Co-based alloy using a high power carbon dioxide laser. The microstructure and the constituent phases and corrosion resistance of the clad layer were investigated. The results show that if laser treating parameters were appropriate, the microstructure of clad layer would be very fine and its corrosion resistance is the best. The corrosion resistance was also improved as reflected by a reduction in the current density of least one order of magnitude as compared with the as-received 2Cr13 stainless steel specimen at the same potential. The improvement in corrosion resistance is due to the increase in Co and Cr content in the cladded layer. Under the condition of high temperature PbSO 4 salt corrosion, high Co content promoted the formation of fine CoO, CoO·Cr 2O 3.The fine dendritic structure and the Co-based alloy oxides help to retard the penetration rate of the sulphur ion which induces the intergranular corrosion.