Abstract: To reveal in depth the smelting/reduction mechanism of chromium ore in converter, the dissolution rate of natural chromium ore in definite shape in CaO-SiO2-MgO-Al2O3 slag system was determined, and a kinetic model for its dissolution process was developed on macrokinetics theory. The results showed that the dissolution process of chromium ore is controlled by the surface dissolution reaction on conditions of the experiments we did, where the temperature has significant effect on the reaction rate constant of chromium ore dissolution. The calculated value of dissolution activation energy is 524.52 kJ/mol. The dissolution rate of chromium ore in slag increases with reaction temperature.