Abstract: Based on the principle of Coriolis force and the structure of 120 t combined side and top blowing AOD converter,the relationship between Coriolis force and the AOD was analyzed and calculated theoretically. The results show that Coriolis force affected AOD's flow field by the action on the gas flow of top and side lances. As to the AOD converter in this research,it is found that the deflection angles of top gas and side gas from outlet to bath surface generated by Coriolis force were 7.92×10^-8 (°) and 1.88×10^-4 (°),respectively,showing that the influence of Coriolis force on side gas was greater than on top gas.