Abstract: During strip cold rolling, tension can alter the deformation resistance of the strip, thereby inducing fluctuations in thickness of strip; whereas variations in strip reduction, in turn, trigger changes in strip tension. Under the mutual interaction between tension and thickness, tension-thickness coupled fluctuations arise. Such fluctuations adversely affect both the thickness accuracy of the product and the stable operation of the mill. Focusing on the frequent occurrence of tension-thickness coupled fluctuations during thin-gauge strip rolling on a Sendzimir 20-high reversing cold rolling mill, this study investigates the structural principles of thickness control, tension control, and the inertial compensation function of Automatic Gauge Control (AGC). As demonstrated in this study, sudden fluctuations in the inlet strip linear speed are identified as the root cause of tension-induced elastic oscillations.The interaction between these elastic oscillations and AGC roll gap adjustments gives rise to tension-thickness coupled fluctuations; consequently, the inertial torque compensation adjustment of AGC must remain fully effective throughout the entire rolling process.To address this requirement, the calculation procedure for AGC inertial compensation torque is deduced, and the factors contributing to the failure of AGC inertial torque compensation are analyzed. By optimizing the torque dead-zone parameters of the uncoiling drive and enhancing the tension setting during the tail rolling stage of thin-gauge strip, the effectiveness of AGC inertial torque compensation is maintained throughout the rolling process, and tension-thickness coupled fluctuations are eliminated. Furthermore, a variable-speed integral control algorithm is employed to suppress tension-induced elastic oscillations, thereby improving the control precision of the tension closed-loop system. After system optimization, tension-thickness coupled fluctuations during thin-gauge strip rolling are notably mitigated, achieving a steady-state tension control precision of ±3% and a thickness control precision of ±2 μm.