An internal defect test block for sound and vibration detection of post insulators consists of three post insulators in the same specification, wherein holes 3a are distributed in the cementation parts between porcelain bottles in an upper flange plate 2a and a lower flange plate 2a of the post insulator 1a and the flange plates; beveling openings 4b are formed in porcelain bottles in an upper flange plate 2b and a lower flange plate 2b of the post insulator 1b; beveling openings 4c are formed in porcelain bottles in an upper flange plate 2c and a lower flange plate 2c of the post insulator 1c, and holes 3c are distributed in the cementation parts. The test block is suitable for calibrating the sensitivity of the post insulators through sound and vibration detection and has the advantages of vivid detect simulation and accurate detection result.