Abstract: To reduce the slag sticking onto the snorkel of the ladle during the ladle alloying treatment station (LATS) process, CaO-CaF₂ (the mass ratio of CaO/CaF₂ is 1:1) was employed as the modifier of the LATS refining ladle slag. The effect of CaO-CaF₂ on the melting point, viscosity, and desulfurizing capability of the ladle slag was investigated. The melting point of the unmodified ladle slag is 1439℃. When adding 20wt% CaO-CaF₂, the melting point is decreased to 1327℃. At 1500℃. the viscosity of the unmodified ladle slag is 6.5 Pa.s, which can be decreased lower than 2 Pa.s by adding more than 10wt% CaO-CaF₂. The experimental results of desulfurization of the melts show that the desulfurizing power of the ladle slag can be enhanced by adding CaO-CaF₂.