Abstract: The analysis of tension AGC system in the tandem cold mill shows that it is a time-varing dynamic system, so that the minimum variance self-tuning regulator is used. After the system is identified and simulated, the results how that the control effect of self-tuning regulator is better than that of PID regulator and the recursive least square with forgetting factor is a better identification algorithm. The application of self-tuning regulator in an actual tention AGC system shows that the gauge deviations of the controlled strip are greatly decreased.