The invention relates to a cold-hot impact three-stage coal breaking device which comprises a bearing pedestal, a walking mechanism, a liquid nitrogen storage steel bottle, an air vortex tube, a water storage tank, a heat exchanger, an air heater, a jet pump, a jet fan, a liquid nitrogen boosting pump, an air heating pipe, a water cooling pipe, a liquid nitrogen cooling pipe and a jet bit, wherein the lower surface of the bearing pedestal is connected with the walking mechanism; the liquid nitrogen storage steel bottle, the air vortex tube, the water storage tank, the heat exchanger, the air heater, the jet pump, the jet fan and the liquid nitrogen boosting pump are all mounted on the upper surface of the bearing pedestal through a sliding rail and are connected with the upper surfaces of the bearing pedestal in a sliding manner. The implementing method comprises four steps of prefabricated hole drilling, prefabrication of a coal breaking group, impact coal breaking operation and drilled hole sealing. According to the cold-hot impact three-stage coal breaking device, on one hand, the working efficiency of drilling operation and the drilling permeability-increasing quality are improved, and the gas extraction is reduced; on the other hand, the gas extraction operation safety and the reliability are improved.