Abstract: Acoustic vibration detection is the scope of an acoustic nondestructive testing and also belongs to the scope of modal testing and analysis. Because the reaction of acoustic vibration detection is the overall strength of the components, the detection time is short and action is very simple. One can use insulated rod to do detection by touching the flange parts of the post insulator. First the model of insulator was established and then ANSYS software was used to calculate modal information. By setting the defects and by the comparison of modal information of post insulators with and without defect, one can analyze the feasibility of the acoustic vibration testing technology in the application of the post insulator intensity.