In order to solve the problem of data sharing, equipment versatility, network congestion and other issues in the current power transmission and transformation equipment online monitoring network, based on the technology of Internet of Things, this paper employs a two-level communication network structure of an access network and an aggregation network to design communication network of substation and transmission lines, solving the problem of communication network congestion by the traffic control and redirection of the aggregation network. Heterogeneous double network dual channel design method is proposed to improve the communication network fault tolerant ability and realize a together application of on-line monitoring equipment and assets inspection. Simulation calculation reveales that long distance point to point communication, single jump distance relay, stable bandwidth and bit error rate are better meet the requirements. A design scheme of wireless Mesh+OPGW fiber is proposed as an effective means for transmission lines to realize on-line monitoring signal remote transmission, and tested and verified on site.