In this paper, the wetting and corrosion behavior between medium and low carbon mold flux and Al 2 O 3 -ZrO 2 -C nozzle refractory were studied through a high-temperature wetting experiment. Combined with microstructure analysis, the corrosion mechanism of low carbon mold flux on nozzle slag line material was clarified. The results show that the wettability of low-carbon mold flux and Al 2 O 3 -ZrO 2 -C nozzle refractory is better, compared with the traditional medium carbon mold flux, the contact angle between low-carbon mold flux and Al 2 O 3 -ZrO 2 -C material is smaller and the mold flux spreads faster on the nozzle surface at the same temperature range. According to the microstructure analysis, the corrosion degree of low-carbon protective slag on the ZrO 2 -C material of the nozzle slag line is serious, and the corrosion depth is large. Due to the influence of carbon content, the wettability between low-carbon mold flux and ZrO 2 -C material of the nozzle slag line is better, which provides favorable kinetic conditions for the dissolution and penetration of low-carbon mold flux into the nozzle. In addition, compared with medium carbon slag, the carbon concentration difference between low-carbon mold flux and nozzle material is larger, resulting in greater diffusion driving force of carbon atoms, which affects the wetting, dissolution, and chemical reaction of the interface between the two phases.