In the intelligent power distribution network, there are not only tree-topology but also ring-topology, mesh-topology and so on. To establish the power line channel models of the distribution networks with these special topologies and analyze the factors that influence the channel characteristics is the premise and the important basis for the application of the PLC in smart distribution network. This paper presents a universal channel modeling method based on information nodes which is suitable for different network topology. Based on this method, the influence laws of multiple factors on channel transmission characteristics under ring topology is analyzed through simulation, such as the lengths between transmitter and receiver, branched line lengths, branched load impedances and number of branches. The analysis of the influence on the signal attenuation is stressed. The correctness and general applicability of the proposed approach and the conclusions are verified through lab measurements. The proposed modeling method and the conclusions provide necessary theoretical basis and technical means for power-line communication modulation method.