The online monitoring system for transmission cables and channels fully considers the operational status of suppliers and users in the power industry, as well as some existing problems in the current monitoring systems for underground power cable networks. Adhering to the principles of technical reliability and advancement, scalable architecture, system compatibility and stability, and the balance between cost and maintenance, it establishes a scientific online monitoring system for cable bodies and their environment. The system utilizes the most advanced intelligent monitoring and IoT technologies, relying on the power network management information platform architecture, and can continuously and reasonably achieve cable online monitoring based on the continuous growth of the information platform.