The invention discloses a suspension-type composite insulator with high stability, which comprises an outer box and a mounting plate, wherein an insulator body penetrates through the interior of the outer box; fixing grooves are formed in the top and the bottom of the inner wall of the outer box; the top of the inner wall of the fixing groove is fixedly connected with a first sliding rail; first sliding blocks are slidably connected to the two sides of the outer surface of the first sliding rail correspondingly; vertical blocks are fixedly connected to the two sides of the top of the inner wall of the fixing groove and located on the two sides of the first sliding rail; and first elastic pieces are fixedly connected between the sides, opposite to the vertical blocks, of the first sliding blocks. According to the suspension-type composite insulator with high stability, which relates to the technical field of insulators, the force applied to the insulator can be reduced when the insulator is under pressure, the stability of the insulator is ensured, the stability of the insulator is improved, the insulator is prevented from shaking under pressure to be damaged, unnecessary economic damage is avoided, and the service life of the insulator is prolonged.