The utility model discloses a composite post insulator of mucilage binding structure, including last flange, lower flange and core, cup joint in the through -hole on last flange the upper end of core, the lower extreme of core cup joints in the through -hole on the lower flange, and on the lateral wall of core upper end and the last flange between the inner wall of through -hole, and all pass through threaded connection on the lateral wall of core lower extreme and the lower flange between the inner wall of through -hole, and be provided with first silastic -layer on the lateral wall of core upper end and the last flange between the inner wall of through -hole, all be equipped with the second silastic -layer on the lateral wall of core lower extreme and the lower flange between the inner wall of through -hole, the sealing performance of this insulator is better, mucilage binding simple process, high reliability and high work efficiency, the mucilage binding precision is high.