<p>The oxygen lance structure in converter has an important influence on the blowing effect of the molten pool, and the reasonable structure of oxygen lance can effectively improve the blowing effect of converter. In this paper, the traditional oxygen lance structure of 150t converter is designed and optimized by means of numerical simulation, water simulation and industrial verification. The results show that with the increase of α angle, the central jet velocity decreases and the flow diameter increases. The pressure of the center hole decreases, and the pressure of the outer hole increases. With the increase of the oxygen lance height, the gas flow pressure decreased, but the coverage width of the gas flow increased. Under the same pressure and inclination angle, the flow rate and velocity of the center hole are increased by increasing the hole size. At this time, the flow rate of the outer hole decreases and the velocity decreases, which is conducive to improving the degree of jet convergence of the flow beam and increasing the impact strength of the gas stream on the molten pool. When compared with other oxygen lances, the optimized 4# oxygen lance’s radial distance and effective impact area are 0.354&#xa0;m and 0.322m², respectively, which are relatively high and have good effect. The average dephosphorization rate is 0.09% lower than that of the original oxygen lance, and the data fluctuation of dephosphorization rate is smaller, and the converter is more stable during blowing.</p> Graphical Abstract <p></p>