Abstract: In order to solve the problem of silt accumulation at the tail roller of belt conveyor in coal mine, the paper contrasted the simple cleaning method at present stage, pointed out its shortcomings, put forward the design scheme of auto-cleaning device with two stage spiral transport and expounded the working principle and structure characteristics of the device. The related calculations of the two stage spiral transport were conducted according to a certain type of the belt conveyor tail roller. The overall structure design of the two stage spiral transport auto-cleaning device was made using SolidWorks software, and the overall structure diagram was given. An effective solution had been provided for auto-cleaning the silt and thrown material at the tail roller of belt conveyor in coal mine．