Abstract: The experiments were carried out at 1 600℃ and normal pressure under an Ar atmosphere. The result showed that the copper content (mass fraction) in steel melt of 400g was reduced from about 0.5% to 0.31% and 0.38% respectively when 0.7~0.8g of NH₄Cl or (NH₄)₂C₂O₄ as the decopperizing agents added to the melt. However it is very difficult to reduce the copper content below 0.3% without reducing the pressure of the reaction system.