The continuous refining process which enables to refine the molten iron in stream lined flow was studied the slag metal counter current operating method in runner type reactor. The simultaneous desiliconization and dephosphorization proceeded over 60% in spite of high Si content, while the decarburization was supressed. The simulation model based on the mass transfer in reaction zones with and without O₂ blowing expressed fairly the actual reaction in the reactor. The contributions of the slag/metal reaction zone with out O₂blowing were estimated to be 26-32% for desiliconization and 47-53% for dephosphorization. From the results obtained here, the continuous process for pre-treatment of molten pig iron was conformed to be possible technically.