The invention discloses an environment monitoring and safety early warning system of a transmission line. The system comprises a plurality of on-site monitoring terminals arranged at a transmission line electric pole. The plurality of on-site monitoring terminals are connected with a database server through a GPRS network; and the database server is connected with a plurality of clients. The on-site monitoring terminals include main controllers, signal conditioning modules, GPS modules, interaction modules, power modules, storage modules, and GPRS communication modules, wherein the signal conditioning modules, the GPS modules, the interaction modules, the power modules, the storage modules, and the GPRS communication modules are connected with the main controllers electrically; and the input terminals of the signal conditioning modules are connected to environmental sensors, weather sensors, tilt sensors, and infrared cameras. According to the invention, with a wireless GSM / GPRS / CDMA transmission mode, environment and weather parameters and the like of the transmission line are monitored in real time; and early warning of the abnormal condition of the line is provided. The GPS module can locate the position information of the monitored line segment in real time. When a fault occurs at the line, positioning is performed rapidly and field repairing is performed, so that the emergency disposal efficiency is improved.