Abstract: A new refining desulfurizing agent with good desulphurization property but without CaF₂ was synthe- sized using Panzhihua Iron and Steel Co.blast furnace（BF）slag extracted titanium as main materials and ac- tive calcium oxide as addition agent.The effects and action mechanism of CaO content on the phase composi- tions,melting performance of the slag system and the desulfurizing ratio of steel samples were investigated.At the same time,the sulphur capacity and optical basicity of slag with different content CaO were given by theo- retical calculation.The results show that active calcium oxide can not only increase violently the desulfurizing thermodynamic parameters such as sulphur capacity and optical basicity of the slag,but also can improve the melting performance.When the CaO content of the slag reaches 60 percent,the optical basicity and sulphur capacity of the slag are 0.781 and 15.8×10^-3respectively,the desulphurization property of the slag is the best.The sulphur content of the steel can decrease from 42.4×10^-6to 7.95×10^-6,the desulphurization ra- tio and sulphur distribution coefficient are 81.2 % and 192.6 respectively.A new technology of comprehensive utilization of BF slag bearing titanium is developed through this paper.