In order to promote the resource recycling of titanium contained in waste slag,the melting properties of CaO-Al2O3-SiO2-TiO2slag are studied through melting experiment and theoretical calculation by using thermodynamic software Factsage. The experimental index is the melting temperature of the slag,and the effect factors are binary basicity,the mass percent of Al2O3 and TiO2. The three factors’ change range are as follows,binary basicity 4~7.9,Al2O3 30%~45% and TiO2 1%~7%. The research results are as follows. The effect of binary basicity is significant,but other factors’ effects are not. Under the experimental conditions,the optimal combination of the lowest melting temperature for the slag are binary basicity 6.6,Al2O3 35%and TiO25%,and the corresponding melting temperature is 1 354 ℃. While the content of TiO2 is lower than 3%,the liquid region area has little change and can be ignored. While the content of TiO2 is under the range of 3%~10%,the liquid region is larger when the content of TiO2 is higher. Under the experimental study conditions,the melting properties of this slag system can meet the requirements of refining slag in steelmaking.