Combined with the characteristics of refining slag making of different kinds of steel and different production con-ditions during the refining of molten steel,this paper focuses on the research of general low alloy steel HRB400E series,high quality carbon high carbon steel 65#series and slab general carbon steel Q235B series.On the basis of the original re-fining slag making,the slag making classification control of refined molten steel top slag is further implemented.Through the implementation of refining slag-making classification control measures under different steel grades and different sulfur content,the efficiency of refining slag-making is effectively improved,the quality of steel is steadily improved,the cost of refining system is effectively reduced,and the fine management of steelmaking system is further promoted to a better and deeper development.