The invention discloses a power transmission line monitoring platform. The power transmission line monitoring platform includes a power source module, a monitoring module, a signal transmission module, a main control end and an alarm module; the power source module supplies power for the monitoring module and the signal transmission module; the monitoring module monitors a power transmission line and uploads monitoring pictures to the main control end through the signal transmission module; the main control end controls the power supply of the power source module and analyzes the state of the power transmission line according to the monitoring pictures; and alarms can be given through the alarm module. The invention also discloses a monitoring method of the power transmission line monitoring platform. The monitoring method comprises a power source remote monitoring algorithm and an image early warning analysis algorithm. With the power transmission line monitoring platform and the monitoring method of the invention adopted, image recognition can be performed on the operating state of the power transmission line and potential threats around the power transmission line, and early warning can be performed according to recognition results, and real-time monitoring of the power transmission line can be realized, human intervention is not required, real-time early warning can be realized, and early warning is accurate and reliable.