Abstract: In view of complex transportation conditions in mine roadways, long conveying distances of belt conveyors, and serious potential safety hazards such as overspeed runaway of downward belt conveyors, this paper designs a damping idler based on the main structure and working principle of downward belt conveyors to ensure safe and stable operation of the equipment. The overall structure of the damping idler is elaborated, and its key components are optimally designed. Both simulation and field tests are carried out to verify its speed regulation performance for belt conveyors. The results show that the application of damping idlers can effectively control the operating speed of downward belt conveyors, and reliably guarantee the safe, stable and efficient operation of the equipment.