<p>A model of the dissolutive wetting process for slag-oxide systems is developed, based on the assumption that the shape of the liquid slag droplet on a solid surface is a spherical cap. The model incorporates key factors such as substrate density, slag density, viscosity, as well as the dissolution rate. Numerical simulations are performed using an iterative calculation method, which reveals the spreading dynamics of the dissolutive wetting process. Experimental data for the wetting of slags, including CaO–Fe₂O₃, CaO–SiO₂–Al₂O₃–MgO on Al₂O₃, Fe₂O₃ and MgAl₂O₄ substrates, were used to validate the model, showing good agreement with the predicted results. The calculated dynamic results indicate that the apparent contact angle (<i>α</i>_apt) decreases rapidly at first, followed by a slower decline due to a lower dissolution rate. The wetting process is primarily governed by the dissolution rate, which is significantly influenced by the dissolution driving force (Δ<i>C</i>&#xa0;=&#xa0;<i>C</i>_sat&#xa0;−&#xa0;<i>C</i>_L) rather than the slag viscosity. The development of this model enhances the understanding of the dynamic dissolutive wetting process, including time variation in droplet size, formation of corrosion pit, and changes in liquid composition and its properties.</p>