Abstract: A nearby electromagnetic stirring system was provided for a ladle refining furnace, where the velocity distribution of liquid metal on the interface between simulated slag and liquid metal was measured and analyzed with Doppler ultrasonic velocimetry so as to determine the important metallurgical parameters such as the critical velocity of slag entrapment in furnace, as well as the relevant parameters of actual ladle furnace. The results showed that the electromagnetic stirring can effectively enhance the internal flow of liquid metal so as to improve its internal kinetic conditions significantly. The electromagnetic stirring is therefore an efficient means to improve the efficiency of ladle refining. Different electromagnetic stirring intensity should be introduced to meet different refining process requirements for commercial production in accordance to the determined critical velocity of slag entrapment.