The invention discloses a high altitude grounding device grounding clamp mechanism comprising a pedestal; the top of the pedestal is provided with a wiring pile head and clamp arms; the wiring pile head is connected with a ground line; the clamp arms comprise a first clamp arm and a second clamp arm respectively hinged to the top of the pedestal through a hinge portion; the first and second clamp arms are sleeved by a mobile chuck; the mobile chuck moves upwards to realize a clamp motion, and moves downwards to realize a release motion; a thread hole is arranged in the pedestal, a rotary shaft penetrates the thread hole, and is screwed with the thread hole; the top of the rotary shaft is fixed with the mobile chuck; the bottom of the rotary shaft is fixed with a clamp board. The high altitude grounding device grounding clamp mechanism allows repair people to fast ground, is simple in structure, and the grounding clamp and release motions are simple and reliable; the high altitude grounding device grounding clamp mechanism is high in grounding operation efficiency.