Abstract: Controlling overprint error is an important for modern printing technology, and the displacement deviation of press cylinder surface in high-speed rotation state is a major cause of overprint error. The real-time monitoring system for detecting the tangential displacement deviation in rotating parts was designed and implemented. Photoelectric detection and A/D mixed-signal processing method was used to realize real-time monitoring of the press overprint error, which could be used for research and manufacturing process of high precision printing machinery. Barcode coding technology, virtual calibration technology and real-time monitoring technology for tangential displacement deviation and self-adaptive dynamic balance technology were used in the system, and the measuring precision was controlled within 10m.