Unavoidably, mining tunnels have locomotives, long conveyor belts, cages, metal mesh supporting and so on these objects, The existence of these objects affects electromagnetic wave propagation in tunnels to some extent. The text regards the tunnel as a waveguide, through experimental measurement and fitting method to study on attenuation of electromagnetic wave in conveyor belt roadway. The experimental results show that: the attenuation of the electromagnetic wave is connected with the existence of long conveyor belts and the received frequency; The existence of conveyor belts increases the attenuation of the electromagnetic wave; the higher the frequency of the electromagnetic wave is, the smaller the attenuation is; 900 MHz is the optimum frequency to study mine wireless communication; In the roadway with width greater than height, horizontal mode is more suitable for communication than vertical mode. The results in this paper provide more powerful support for the coal mine roadway wireless communication, and provide reference value and practical significance for the further study of the electromagnetic wave propagation characteristics.