The present invention discloses a radiator for high-voltage vacuum breaker; the radiator is configured in a pair, composed of an upper radiator and a lower radiator, mounted on the top sealing cover of the vacuum breaker and the flange at the bottom wiring terminal, respectively. The fin base of the upper radiator is a disk, in diameter of 320-380mm. Mounting holes are arranged evenly along the circumferential direction around the fin base. Fins are arranged at even central spacing of 10-20mm in parallel on the fin base. The fins are broken along the length direction, and the gaps formed by breaking are distributed in a stagger manner. All the fins in the outer layer are filleted. The lower radiator is in overall circular ring form. For the convenience of installation, the lower radiator is bi-parted in symmetry. Two rows of mounting holes are arranged in a staggered manner on the base of the lower radiator. Fins distributed in a radial manner are arranged on the fin base; the included angle between center lines of adjacent fins is 4-8 DEG. The outer sides of the fins are filleted to suppress corona.