The continuous annealing process of strip steel is aimed to archive the required physical and mechanical properties. During this process, strip temperature is of great importance for controlling metallurgical transformation and grain size. This paper describes the modeling of the heating process in a horizontal annealing furnace used for producing stainless steel. The steady-state model is designed to predict strip temperature in the heating section, so it can simulate the annealing process of new varieties of steel never been produces. The strip temperatures predicted by model well correspond to the field data. This confirms the correctness and accuracy of the model.