Abstract: There were weak temperature regulation, large delay and overshoot for quick-frozen process of margarine production system, a new temperature control program designed to achieve accurate control in quick-frozen process, which based on by-pass adjustment was proposed for the first time. Steady-state mathematical model and basic control rules of the by-pass regulation were established. The influence caused by disturbance could be predicted by using simulation technology, the accurate mathematical control based on by-pass adjustment was integrated into control system of margarine production system. Experiment was carried out to study by-pass adjustment's effect under various disturbances. The experiment research results showed that the accurate mathematical control method based on by- pass regulation could achieve the operation optimization of margarine production system. The delay and overshoot among control were small, temperature control effect was remarkable.