The slag blocking cone is a refractory product similar to a vertebral body and equipped with a guide rod with a small diameter. There are three steel taps to prevent the molten steel from flowing out. In the middle and later stages of converter tapping, the guide rod part of the slag blocking cone is inserted into the tap hole in the furnace. When the molten steel runs out, the vertebral body blocks the tap hole, thus preventing the steel slag from flowing into the ladle. The slag blocking efficiency can reach more than 98% . The use of slag blocking cones has a good effect on stabilizing molten steel composition, reducing molten steel rephosphorization phenomenon, improving molten steel quality, improving alloy element absorption rate, and reducing refractory consumption.