The invention discloses a coal exploitation device, and particularly relates to an alternative-current hydraulic impact type coal cutter which comprises a barrel coal cutter body, a traction part and rocker arms, wherein one end of each rocker arm is hinged to the barrel coal cutter body; the rocker arms are further connected with height adjusting cylinders; the other ends of the height adjusting cylinders are fixed on the barrel coal cutter body; an alternative-current hydraulic impact part is hinged to each rocker arm at each end of the barrel coal cutter body. By adopting the alternative-current hydraulic impact type coal cutter, the blocking rate of raw coal production can be greater than 70% and can be increased by 40% when being compared with that of a conventional barrel type coal cutter, and the comprehensive quality of coal is also greatly improved.