Abstract: Link attenuation is an important index to measure the transmission quality of the carrier channel.In order to predict the channel attenuation characteristics,a new method for power line communication（PLC）channel voltage attenuation in medium voltage distribution network based on partial reflection theory is presented.Using the transmission line theory and partial reflection theory,the voltage transmission discipline is derived with the transmission line of terminated load and the transmission line cascade of different characteristic parameters.Then,PLC channel mathematical models of medium voltage distribution network with and without branch lines and distribution transformer lines with loads are built.According to the medium voltage distribution network topology,the model is cascaded from the end of the distribution network to the carrier source to get the PLC channel model between the end node and the source node.And the transmission characteristics of the carrier signal at each node are analyzed.The method is simple in principle,fast in calculation and easy to be transplanted.The results of simulation and RLC circuit experimental show the correctness of the proposed modeling approach.