ABSTRACT In top-blowing steelmaking, the flow behaviour of molten steel during supersonic jet impact into the molten bath is crucial for the refining process. In this study, the effects of lance height and operation pressure on velocity distribution and the flow characteristics of the molten bath during the swirl-type oxygen lance blowing process in a 260t converter were explored. The results demonstrate that compared to the traditional oxygen lance, the stirring efficiency of a molten bath with the swirl-type oxygen lance is improved due to the tangential momentum of the jet and the increase in cavity diameter. As the lance height increases, the flow is improved at the bottom and surroundings of the molten bath, and the dead zone volume of the molten bath decreases first and then increases. The best stirring efficiency is achieved at H = 40de. As the operation pressure increases, the impact strength of the jet increases, the flow at the upper zone of the bath is significantly improved, and the dead zone volume decreases.