At present, due to various reasons, the accident in the construction that the drill of the rotary drilling rig dropping off into the hole occur all the time. It is difficult to salvage the drill bits because it dropped in the mud at the bottom of the hole which deepest reaches tens of meters. At this stage, the way to salvage drill bits generally has the disadvantages of high cost, unsafe and low success rate. Therefore, a machine hand is developed which can be installed on a rotary drill pipe and lowered to a deep hole to salvage the drill bit. Rotating the drill pipe through the rotary drilling rig, controlling the opening and closing of the machine hand, so that it can grasps firmly the protruding square set on the top of the dropped drill bit, and the machine hand can connect with the dropped drill bit, then the rotary drilling rig salvaged the drill bits through lifting the drill pipe，can achieve results that fast, accurate, safe and economical.