Abstract: In allusion to problems that current protection device of belt conveyor in coal preparation plant is lack of dynamic anti-assault monitoring function and rotating parts of conveyor easily lead to injury accident and other issues, the paper proposed a design scheme of anti-assault safety protection system of belt conveyor in coal preparation plant，and introduced overall design, equipment selection and detector layout of the system. The system uses pyroelectric infrared detector, active infrared intrusion detector and infrared electronic network to detect human body near rotating parts of conveyor, and gives tips, alarm or shutdown for protection. Field industrial test results showed that the system can effectively prevent injury accident caused by rotating parts of conveyor.