Abstract: Powder injection desulphurization and denitrification refining process with the ladle-cover was studied. The experimental results showed that in first stage, desulphurization ratio reached the 50% and denitrification ratio reached the 30%. In second stage, desulphurization ratio reached the 65% and denitrific-ation ratio reached the 40%. The process reduced sulphur of molten steel to 4×10^-6 and nitrogen of molten steel to 12×10^-6. On the some time reduced the nitrogen. The experiment result supplied basic theory for the commerical test of the process.