This invention relates to a method for smelting CO2 corrosion resistant steel. The method comprises: (1) desulfurizing and dephosphorizing iron melt; (2) pouring semi-steel melt into a decarbonization converter, heating, blowing and decarbonizing; (3) adding high carbon ferrochrome at a certain carbon content and temperature; (4) blowing oxygen and heating for decarbonization so that the Cr and P contents in the steel melt are above 8% and below 0.020%, respectively; (5) alloying; (6) heating and adjusting the composition in a refinery LF furnace; (7) finely adjusting the composition and degassing in a refinery RH furnace, and casting in a mold to obtain steel ingots. The method can be used to manufacture CO2 corrosion resistant steel L80-13Cr.