Abstract: In view of problems that basic path loss model based on received signal strength indicator (RSSI) is established on visual range between sending node and receiving node and it is not conformed to transmission characteristics of mine electromagnetic wave, the paper proposed an improved transmission path loss model of mine electromagnetic wave. On basis of basic model only considers attenuation factor, the improved model adds coefficient of multipath parameter and employs the least square method to calculate the two parameters. The calculation and Matlab simulation results show that the value obtained by use of the improved model is closer to measured value and has less error, and received power and transmission attenuation decrease with increasing of node interval.