Abstract:The application situation of the sublance of 120 t converter furnace in Yinshan steelmaking plant of Laisteel was introduced. The running of sublance got stable by optimizing the mathematical model and amending the order systems lastly, and by this the converter down furnace operation had canceled basically,the steelmaking operation process of converter had optimized. The kinds of indicators of converter got raised, the hit rate of carbon and temperature had reached above 90%, smelting cycle had shotened 4 minute averagely, the manufacturability of converter had increased 10%. The consumption of steel and iron materials had reduced 11 kg/t. Meanwhile the consumption of refractories had reduced, the quality of steel had enhanced, the steel composition had stabilized. All of that had created advantage situation for the development of highquality varieties of steel and realized the conversion from experience steelmaking to smart steelmaking.