The invention discloses an efficient coal underground gasification furnace and a construction method thereof. Furnace profile construction adopts coal seam directional drilling and ground vertical drilling technologies, and the underground gasification furnace is constructed through butt joint of gas collecting channels, gasification channels and gas outlet channels with vertical drilling holes inignition areas in coal seams, wherein the gas collecting channels, the gasification channels and the gas outlet channels are constructed through directional drilling. Moreover, the advanced coal seamdirectional drilling technology is utilized, meanwhile, aiming at the coal seams of different occurrence conditions, the underground gasification furnace, the gas collecting channels, gas outlet systems and the ignition areas which are integrated are constructed, implementation is easy, and the construction period is short. The structure is reasonable, the efficient coal underground gasificationfurnace and the construction method thereof are suitable for the novel efficient coal underground gasification furnace profile of the coal seams of the different occurrence scales, and the related problems that the coal resource gasification utilization rate is low, direct product gas contains dust, the high temperature, the high pressure and inconsistent components, and the bottoms of gas outletsare instable are solved; and stable gas outlet is guaranteed, implementation is easy, the construction period is short, and long-term stable and efficient operation of the gasification furnace is guaranteed.