A heating tank for quality improvement of high-yielding lignite by drying comprises a moisture removal pipe, a loading conveyor, a tank body, a sealing cap, a heat supply air blower, a first powder coal/coal gas supply centrifugal fan, a powder coal/ gas pipe supply line, a first powder coal/coal gas heating furnace, an ash storage hopper, a heating pipe and a product output machine, and further comprises a second powder coal/coal gas supply centrifugal fan, a second powder coal/coal gas heating furnace and a supplement heating pipe, wherein the heating pipe and the supplement heating pipe sleeved outside the heating pipe are installed in the tank; the supplement heating pipe is shorter than the heating pipe; the heat source output end of the first powder coal/coal gas heating furnace is connected with the bottom of the heat supply air blower; the heat source output end of the second powder coal/ coal gas heating furnace is connected with the side or the top part of the sealing cap; and one end of the second centrifugal fan is connected with the second powder coal/ coal gas heating furnace. The tank provided by the invention has the advantages of reasonable structure, high efficiency, good safety, and greatly improved efficiency compared with traditional drying and heating equipment.