A coal powder boiler with high-temperature SNCR (selective non-catalytic reduction) denitration reactors comprises a hearth, wherein a screen-type heating surface and a first convective heating surface are sequentially arranged on the upper part of the hearth in the moving direction of flue gas; one or more high-temperature SNCR denitration reactors are connected onto a connecting flue of a flue gas outlet of the hearth and an inlet of a tail flue, or arranged on the two sides of the flue gas outlet of the hearth; when the high-temperature SNCR denitration reactors are arranged on the two sides of the flue gas outlet of the hearth, the flue gas outlet of the hearth is connected with the inlet of the tail flue; a second convective heating surface, a coal economizer and an air preheater are sequentially arranged inside the tail flue in the moving direction of the flue gas; coal is burned inside the hearth, the generated flue gas exchanges heat with the screen-type heating surface and the first convective heating surface which are arranged at the upper part of the hearth, and then carries coal ash to enter the high-temperature SNCR denitration reactors, a part of the coal ash is separated out, and the flue gas carries a small amount of the coal ash to enter the tail flue. The coal powder boiler increases the denitration efficiency.