The invention discloses a surface-breakdown-type vacuum switch trigger electrode comprising a low-voltage electrode, a molybdenum ferrule, a ceramic tube, a metal trigger electrode, a molybdenum ring, a semiconductor coating layer and a trigger electrode groove. The ceramic tube is arranged in a through hole between the low-voltage electrode and the center of the molybdenum ferrule and tightly contacts with the molybdenum ferrule to guarantee electrical insulation between the low-voltage electrode and the metal trigger electrode; the metal trigger electrode is arranged in a through hole at the centers of the ceramic tube and the molybdenum ring to guarantee equal potential of the molybdenum ring and the metal trigger electrode; the molybdenum ring is arranged on the upper portion of the ceramic tube; the semiconductor coating layer is arranged on the tube wall of the ceramic tube between the molybdenum ferrule and the molybdenum ring; the direction of the semiconductor coating layer is in accordance with the direction of a gap electric field applied by a high-voltage electrode; the trigger electrode groove is formed in the low-voltage electrode on the periphery of the molybdenum ferrule, the molybdenum ring and the semiconductor coating layer. The surface-breakdown-typed vacuum switch trigger electrode can solve problems of short service life, poor high temperature resistance and easiness in damage by ablation of the existing trigger electrodes.