The invention relates to the technical field of a power transmission line state monitoring system, and provides a power transmission line state monitoring agent. The agent belongs to an access layer in the power transmission line state monitoring system, is connected with state monitoring devices via I1 interfaces based on TCP or UDP, and communicates with a main station system via an I2 interface based on gsoup. According to the power transmission line state monitoring agent, functions of improved data access and forwarding, state monitoring device management, and self-management are provided, various state information of a power transmission line in a special environment is obtained via the state monitoring devices, the current state of equipment on the power transmission line is determined via processing and analysis of an on-line monitoring platform, and an important significance is attached to the prevention of power transmission line accidents, guarantee of safety and reliability of the power transmission line, and normal operation.