Abstract: Cooling is the process by which the temperature of food is decreased to a final temperature above freezing during food processing. Simulating the process has a great significance on theory and practice. For heat conduction on a one-dimensional unstable state as during the cooling process of plain food, it is an easy and feasible method to establish differential equations to solve problems with numerical prediction. Based on finite difference methods, the cooling process is simulated with powerful MATLAB. This new method can simplify operations. Results show that rules of cooling time of food, cooling speed and inner temperature fields obtained from MATLAB is in agreement with the practical situation. The simulation provided an important theoretic basis for manufacturing equipment for chill storage and freeze storage of food, for studying technology and for automatic monitoring and automatic control.