The invention belongs to the field of signal detection and automation control of rolling mills, and relates to a device for suppressing vibration of a rolling mill. The device for suppressing the vibration of the rolling mill is characterized by comprising a rolling mill vibration signal source, a vibration suppression signal generator, a vibration suppression actuating unit and the rolling mill, wherein the rolling mill vibration signal source is composed of rolling mill torsion vibration signals, rolling speed signals, rolling mill vertical vibration signals and rolling pressure signals, the vibration suppression signal generator is composed of a signal input module, a filter processing module, a phase recognition module, a vibration suppression signal module and a signal output module, and the vibration suppression actuating unit is composed of a main drive speed setter and a hydraulic roll gap setter. The device for suppressing the vibration of the rolling mill has the advantages that vibration suppression damping signals are generated by the vibration suppression signal generator according to the rolling mill vibration signal source and sent to the main drive speed setter and the hydraulic roll gap setter of the vibration suppression actuating unit so as to participate in control of the rolling mill to reduce the vibration energy of the rolling mill, so that the rolling mill can be prevented from vibrating severely, chatter marks on a roller and the surfaces of strips are eliminated, and therefore the surface quality of products is improved, and the on-line service life of the roller is prolonged.