Paper-transferring mechanism is the key component influencing overprint precision; excess vibration of paper-transferring gears can cause inaccurate overprint. PULSE vibration test system was applied to test the vibration between paper-transferring gear and the wallboard of the paper-transferring mechanism of a printing press, and the dynamic response of paper-transferring gear and the wallboard was obtained. It concluded from the experiment that excessive vibration of wallboard is the main cause of the excessive vibration of paper-transferring gear. Improving design was made to the wallboard. The correctness of the inference was verified from time and frequency domain to compare the improved wallboard with original one. This method can be applied to dynamic design of other structure of printer.