When there appeared catastrophic asymmetrical flatness defects in rolling processes, especially when the incoming strip is with a wedge shape, the tilting roll can hardly eliminate these defects completely. Moreover, the overshooting of tilting roll will lead to strip break. In order to improve the ability of cold rolling mill for asymmetrical flatness defects control, performance of the work roll asymmetrical bending as well as the intermediate roll asymmetrical bending has been analyzed, based on the actuator efficiency factors of them. In addition, for the purpose of obtaining accurate efficiency factors matrixes of actuators, a self-learning determination model of actuator efficiency factors was established in accordance with the practical rolling processes. In this paper, a 1250 single stand 6-H reversible UCM cold mill was taken as the object of this study, with efficiency factors of asymmetrical roll bending analyzed, which provides a theoretical basis for better flatness control. Analysis shows that the asymmetrical roll bending is significant for asymmetrical flatness control.