According to the ion and molecule coexistence theory of slag and combining the viscosity and surface tension of chromium-containing converter slag measured by predecessors, the calculation model of viscosity and surface tension about temperature and structural units had been established to predict the viscosity and surface tension of chromium-containing converter slag. The calculated values of the model agreed well with the measured values in the literature, indicating the model could help to predict the viscosity and surface tension of chromium-containing converter slag. The results showed that the viscosity and surface tension of slag increased with the increase of Cr₂O₃ content, while decreased with the increase of FeO content. Cr₂O₃ had the greatest influence on the surface tension. The viscosity of slag increased with the increase of basicity. With basicity increasing, the viscosity of slag increased, and the basicity had the greatest influence on viscosity, while the surface tension first increased and then decreased, and reached a maximum value with basicity of 1.8.