Abstract: Converter slag is an important by-product of the steelmaking process, which seriously affects the comprehensive utilization of converter slag due to the enrichment of phosphorus in the slag. Bottom-blowing nitrogen can increase the contact area between the reducing agent and slag, and improve the phosphorus removal efficiency of converter slag. The article adopts a numerical modeling method for the bottom blowing of nitrogen to the slag before converter slag sputtering and furnace protection, and investigates the effects of the number of converter bottom blowing nozzles, bottom blowing flow rate and bottom blowing nozzle position on the flow field of the molten pool. Simulation results show that the average turbulence energy of four nozzles is 2.5 times of that of a single nozzle, and the bottom blowing loss is lower than that of two nozzles, so the bottom blowing effect is the best. The increase of bottom blowing flow rate from 1.14 m/s to 1.31 m/s has little effect on the reduction of dead zone ratio, and the nozzle flow rate should be minimized under the premise of guaranteeing the mixing effect of the molten pool. Eccentric bottom blowing has a larger dead zone ratio than center bottom blowing, which is not conducive to slag mixing.