A three-dimensional computational fluid dynamics(CFD) model was developed to simulate a 150-t top-blown converter. The effect of different lance heights on the cavity shape was investigated using the volume of fluid(VOF) method. Numerical simulation results can reflect the actual molten bath surface waves impinged by the supersonic oxygen jets. With increasing lance height, the cavity depth decreases, and the cavity area, varying like a parabola, increases and then decreases. The cavity area maximizes at the lance height of 1.3 m. Under the three different lance heights simulated in this study, all of the largest impact velocities at the molten bath surface are between 50 m/s and 100 m/s. A three-dimensional computational fluid dynamics (CFD) model was developed to simulate a 150-t top-blown converter. The effect of different lance heights on the cavity shape was investigated using the volume of fluid (VOF) method. reflect the actual molten bath surface waves impinged by the supersonic oxygen jets. With increasing lance height, the cavity depth decreases, and the cavity area, varying like a parabola, increases and then decreases. Under the three different lance heights simulated in this study, all of the largest impact velocities at the molten bath surface are between 50 m / s and 100 m / s.