Abstract: The disadvantages of the analytical solution and the simplified method were analyzed and a thermal expansion model was established by the finite element method. Based on the data characteristics of the rolls' geometry in a rolling unit, the calculation task was divided into pre-calculation responsible for static data preparation and renewal calculation responsible for renewing dynamic data and thermal expansion. The pre-calculation was called only after roll change and the renewal calculation was called when the thermal expansion data was needed to be updated. This special tailored flow contributes to a much smaller computation complexity in comparison with standard finite element analysis. Furthermore, the corresponding program was compiled according to the tailored flow and its results are in agreement with those by ANSYS, with the accuracy of about 30% higher than the simplified method. Due to high accuracy and short calculation time, this home-made finite element analysis program is promising to be implemented in online applications for evaluating the thermal expansion of rolls.