The invention relates to an energy-saving dryer, which consists of an air inlet preheating unit, a fresh material preheating unit and a drying unit. A preheating pipe is arranged on the inner side, a chimney is arranged on the outer side, and the preheating pipe and the chimney are arranged upwards spirally; a plurality of material barrier sieves and impurity collecting plates are arranged in a drying tower, incline horizontally and are arranged in an inner chamber of the drying tower from top to bottom in a mutual staggered mode, and a preheating material tower inlet and a hot-blast air outlet connected with a blast blower are formed on the top of the drying tower; a jacketed impurity collecting cavity is formed on the upper part of the drying tower, an impurity collecting opening, a temperature regulating air inlet and a preheating air inlet connected with a hot air stove outlet are formed on the middle part of the drying tower, and a hot air stove inlet is connected with an air outlet of the preheating pipe; a discharge hole is formed at the lower end of the drying tower; a radiator is arranged in a preheater, and upper and lower ends of the radiator are respectively connected with a blast blower outlet and the chimney; and upper and lower ends of the preheater are respectively connected with a fresh material inlet and the preheating material tower inlet. The energy-saving dryer has a scientific design, a compact structure, low cost, stable performance and high practicability.