The utility model discloses a solid fuel combustion device with a fire grate obliquely arranged. The solid fuel combustion device with the fire grate obliquely arranged comprises a stove body, a fire outlet formed in the side of the stove body, and the fire grate obliquely arranged in a stove cavity. The upper portion or the top of the stove body is provided with an upper air inlet, the lower portion of the stove body is provided with a lower air inlet, and the stove body is internally provided with the stove cavity. The upper air inlet and the fire outlet are located in one side of the fire grate, and correspondingly, the lower air inlet is located in the other side of the fire grate. The space, above the fire grate, in the stove cavity is a solid fuel containing cavity which is divided into a combusting-preparing area and a combusting area from top to bottom, and the height of the combusting-preparing area is larger than 150 mm. The ratio of the largest breadth width of the fire grate to the height of the fire outlet is not more than 1.5. The height difference between the solid fuel containing cavity and the height of the fire outlet is not less than 150 mm. By means of the solid fuel combustion device, solid fuel can be combusted without pollution.