For the requirements of mechanism activity, the mechanical pairs need certain clearances. To research the precision and stability of high-speed mechanism, it’s need to study the impaction and vibration which is caused by clearance in pair. A vibration experiment set of four-bar linkage with clearances is designed for this goal, and on the experiment set, vibration wave and data are gotten. The data got from experiment set are consistent to the results of theoretical calculation. From the vibration measure and dynamic model, it’s found that comparing to ideal pair, clearance causes impact in pair and the vibration increasing nonlinearly with rotary velocity.