Abstract: Employing Simulated Annealing Algorithm(SAA) and Finite Difference Method, a calcula-tion model of work roll thermal contour was built in a 2800mm 4-high mill of Wuhan Iron and Steel (Group) Co.. The model was a semi-theory practical formula. Its pattern and magnitude were still hardly defined with classical optimization methods. But the problem could be resolved by SAA. It was pretty high precision to predict the values of work roll thermal crown in a rolling unit. After one year application, the results show that the model is feasible in engineering, and it could be applied LO predict the roll thermal contour of other mills.