In order to improve the detection efficiency of egg quality on-line detection mechanism, and reduce eggshell breakage rate in the detection because of mechanical vibration generated, the modal analysis of the detection mechanism key components of the double circular arc cylinder and frame was carried out, by using the finite element analysis software ANSYS, and then it was tested by experiment. The results showed that the vibration frequency of the detection mechanism, lower than 971.28 Hz, could not cause vibration of double circular drum group, and this helped to reduced the eggshell breakage rate. Moreover, the frame frequency was found relatively low and easy to cause vibration, so the vibration reduction design of the detection mechanism was mainly based on the frame. It was a reliable and rapid method to analyze the vibration characteristics of mechanism by using the modal analysis of finite element software ANSYS, and this laid the foundation for the vibration analysis and optimum design of other components of the detection mechanism.