The invention relates to the technical field of power transmission line monitoring, in particular to a power transmission line external force damage prevention monitoring and early warning system andan application method. The power transmission line external force damage prevention monitoring and early warning system comprises a power transmission line state monitoring unit, a power transmissionline damage prevention triggering unit, a video monitoring unit, a front-end control unit, an alarm unit, a communication unit, a rear-end control unit and a power supply unit; the power transmissionline state monitoring unit, the power transmission line damage prevention triggering unit, the video monitoring unit and the power supply unit are all connected with the front-end control unit, the front-end control unit is respectively connected with the alarm unit and the communication unit, and the communication unit is connected with the rear-end control unit. According to the power transmission line external force damage prevention monitoring and early warning system, triggering, analysis and recording are integrated into one body, remote real-time and effective monitoring on hidden danger points of power transmission line external force damage is realized, guarantee is provided for timely and active prevention of external force damage behaviors, the monitoring efficiency is improved,the workload generated by personnel on-site inspection is reduced, and safe operation of a power transmission line is guaranteed.