The utility model discloses an energy-saving hot air drying device. The device comprises a heating chamber and a drying chamber which are connected through an air inlet pipe and an air return pipe; the heating chamber comprises a hot air furnace and an external wall which surrounds the hot air furnace; the hot air furnace is divided into an upper part and a lower part, wherein a combustion chamber is arranged at the upper part, and while a slag discharging chamber is arranged at the lower part; an air collecting device is arranged in the middle part of the hot air furnace; a chimney is arranged on the top part of the hot air furnace; a heat collecting chamber is formed between the external wall and the top part of the hot air furnace; the air inlet pipe is located on the external wall of the heat collecting chamber, and while the air returning pipe is located at the bottom parts of the heating chamber and the drying chamber. The energy-saving hot air drying device has the beneficial effects that the air collecting device is arranged on the lower surface of the combustion chamber to enable full combustion of the fuel, so that the energy can be saved; the air inlet pipe and the air return pipe are arranged between the heating chamber and the drying chamber, and therefore, hot air can be recycled, and as a result, the heat energy utilization efficiency can be raised; moisture removing holes are formed in the bottom part of the drying chamber to remove moisture from the drying chamber so as to improve the drying effect.