The invention discloses a grading dehumidifying device, and relates to a high-temperature waste-gas dehumidifying device. The grading dehumidifying device comprises a shell. The shell comprises a gas inlet, a gas outlet and a water discharging opening; a grading wheel is also arranged in the shell, and is hollow and arranged under the gas outlet, the bottom of the shell is conical downwards, the water discharging opening is formed in the bottommost portion of the shell, a condensation pipe is wound around the outer side of the shell, and a guiding gas pipe extending into the shell is arranged in the water discharging opening, is located under the gas outlet, and sprays outside air upwards. Compared with the prior art, the grading dehumidifying device has the advantages that vapor in waste gas can be separated, and rising of vapor during discharging is avoided; meanwhile, a large amount of heat in waste gas can also be reused in a heat-exchange mode, losses of energy are reduced, and waste is avoided.