The invention discloses a hot air circulating drying machine. The machine is characterized by comprising a drying room, an upper drying chamber, a heating chamber and a lower drying chamber are sequentially arranged in the drying room from top to bottom, the upper drying chamber and the lower drying chamber are communicated with the heating chamber, a heating device is arranged in the heating chamber, the upper drying chamber and the lower drying chamber are divided into an upper left drying chamber, an upper right drying chamber, a lower left drying chamber and a lower right drying chamber through an upper partition plate and a lower partition plate, the upper left drying chamber is communicated with the upper right drying chamber, and the lower left drying chamber and the lower right drying chamber are communicated. The drying machine is reasonable in structure, hot air flow can flow positively and reversely, and unevenness of the dried materials can be effectively avoided; the heating device is arranged in the heating chamber, air is heated, high-temperature hot air enters the drying chamber to dry the materials, finally, the high-temperature hot air is discharged at the low temperature through a heat exchange device, heat energy is recycled, and the energy-saving effect is achieved.