Automatic gauge control (AGC in the article) is the key technology of product thickness accuracy and flatness quality in modern cold rolling mill. Most traditional AGC control algorithms need stable external system conditions and hard to stabilize under complex interference that meets coverage requirements. This paper presents a new anti-interference strategy for AGC control of 20-Hi cold reversing mill. The proposed algorithm introduces a united dynamic weights algorithm of feed forward-mass flow to avoid the complex interference problem in AGC control, the relevant control strategy is provided to eliminate the adverse effects. At the same time, the D-value between feed forward-mass flow pre-computation and thickness measurement deviation is dynamic compared, the final gap position regulation is calculated by developing a set of united dynamic weights between feed forward control and mass flow control. Finally, the output of controllers is sent to actuator though a constant rate smoothing. The proposed strategy is compared with conventional AGC control on Experimental platform and project application, the results show that the proposed strategy is more stable than comparison method and majority of system uncertainty produced by mentioned interference is significantly eliminated.