This paper presents a monitoring method of strip rolling mill based on the digital twin model. Compared with the traditional monitoring methods, this method effectively reduces structure complexity and test cost of the monitoring system. In this paper, the coupling vibration mechanism model of the dynamic characteristics of roll system and bearings of four-high mill was established, and the digital twin model of strip rolling mill vibration was built based on the mechanism model. Consequently, the traditional monitoring test of the rolling mill was carried out to verify the accuracy of the digital twin model. Through analyzing the test results, it can be found that when the rolling force fluctuation is more obvious, the rolling mill roll system vibration becomes more intense. According to this phenomenon, the measures were put forward to suppress rolling mill vibration. In conclusion, the rolling mill vibration monitoring theory based on digital twin model provides technical support and theoretical basis for improving equipment operation stability, reducing test cost and improving product quality.