Abstract: A number of important links in the metallurgical production process are related to interface phenomena, including slag foaming, hot metal desulphurization, refractory erosion, converter blowing, the behavior of inclusions in steel, and so on. Interfacial wettability is an important aspect of the interfacial interaction. By controlling the interfacial wettability between two phases, it is possible to remove inclusions, improve the cleanliness of the molten steel, reduce erosion of the refractory material, improve the life of the lining material, and ensure smooth production and product quality. Thus, it is necessary to analyze interfacial phenomena in ironmaking and steelmaking with respect to interfacial wettability. In general, interfacial wettability can be measured by the contact angle and interfacial tension, and the contact angle and interfacial tension between the molten steel and slag are determined primarily by the surface active element in molten steel and the active surface component in slag. In this study, we analyzed in detail some common phenomena in the steelmaking process from the view of interfacial wettability. With respect to the slag foaming process, we mainly analyzed the effects of the contact angle and interfacial tension on the slag foaming index. To study the hot metal desulphurization process, we considered effects on the desulfurization rate and the utilization and penetration speed of the desulfurizing agent. Regarding the refractory erosion process by molten slag and steel, we primarily studied the effects on the refractory saturation slubility in molten slag, the penetration depth of molten slag in refractory material, and the refractory erosion rate. To study the behavior of inclusions in steel, we considered effects on the nucleation, aggregation, removal, and spatial distribution homogeneity of inclusions. We also summarized the conditions associated with better interfacial wettability with respect to the corresponding phenomena.