30CrMnSi is quenched and tempered steel with medium hardenability, and good mechanical properties. However, the anti-corrosion of the weld heat affected zone will be decreased, which will lead to the worse overall properties of parts. The anti-corrosion properties of heat affected zone will be improved by YAG laser treatment according optimized processing parameters. The microstructure of the modified heat affected zone was observed and analyzed in this paper. And the anti-corrosion property was studied also. The results showed that the anti-corrosion property of heat affected zone will be improved by laser remelting technology. The laser anti-corrosion is the effective method to enhance anti-corrosion property.