On the basis of laboratory and industrial converters,some tests were carried out in order to improve dephosphorization in steelmaking. The results show that stirring intensity,conversion temperature of carbon-phosphorus oxidation reactions,carbon content of hot metal and slag compositions have significant effects on the dephosphorization under the top and bottom blowing conditions. A formula for the distribution ratio of phosphorus was established,which included carbon content and agitating factors,and a dephosphorization reaction rate equation was verified by test data. While the oxidizability of the molten bath was investigated,a blowing index for dominating the iron-oxidation in the molten bath was suggested to adjust the distribution of oxygen between slag and hot metal. In practical operations,both the dephosphorization and the peroxidation of iron in the molten bath were improved by controlling the top and bottom blown conditions and the slag compositions.