The smelting reduction of vanadium–titanium magnetite (VTM) in an oxygen-rich side-blown bath smelting furnace (OSBF) is a promising process. In the present work, the multiphase flow characteristics in an OSBF are investigated by numerical simulation. Suitable models were first obtained by experimental validation, and then applied to the simulation of industrial OSBF. During the validation process, the coupled level-set volume of fluid (CLSVOF) model was used to track the gas–liquid two-phase flow. Four turbulence models (the standard k–ε model, the RNG k–ε model, the realizable k–ε model, and the SST k–ω model) were compared with the experiment results. The results indicate that the gas–liquid multiphase flow in the OSBF can be adequately worked out by coupling the CLSVOF model together with the realizable k–ε model. The simulation of the industrial OSBF process reveals the movement behavior of the gas and the flow characteristics in the bath. In addition, the effects of the gas flow rate on the gas–liquid multiphase flow in the OSBF process were also studied, and 600–800 Nm3 m−2 h−1 was recommended as an appropriate gas flow rate range during the OSBF process.