A mathematical model has been built to numerically predict the thermal history of thin slab during CSP (compact strip process) rolling. To estimate the temperature distribution in the slab more accurately, the mathematical model combines heat transfer in the slab, in the roll, and at the roll-slab interface during bite. The numerical results agree with on-site running data, which proves the reliability of the mathematical model. The results show that roll chilling has a significant effect on the temperature distribution in the slab.