This paper relates to a high reliable communication method for the terminal of a networked and distributed power supply system. Terminal refers to the realization of two-way communication between high voltage source of distributed power supply and laden multiple electrical appliances. Due to the characteristics of long distance, complex electromagnetic environment and small amount of communication information between the voltage source and the electrical appliance, this paper designs a new kind of high reliable communication method along with high-voltage transmission, narrow-banded and single-ended synchronous [1,2,8]. Under the condition of satisfying the communication capacity and reliability, this method has been successfully applied to the city network and LED street lamp management system with the advantage of simple circuit design and inexpensive manufacturing cost.