The invention discloses a line inspection system and method of a transmission line. The line inspection method of the transmission line comprises the following steps: arranging an RFID electronic tag on a pole tower of the transmission line to be detected; acquiring RFID electronic tag information to obtain the name, the number and the located geographical position of the pole tower; acquiring a video image signal of the transmission line connected with the pole tower, and transmitting the video image signal to a monitoring center by the way of a video stream; intercepting a video frame of the video stream every prediction time by the monitoring center; comparing the video frame with a preset transmission line image, if the comparison result exceeds a preset range, judging that the transmission line is abnormal and stored. The method disclosed by the invention does not require line-inspection maintenance personnel to inspect the line on spot, and then the monitoring center can automatically analyze and judge abnormalities of the transmission line and find out fault points, and then the abnormalities of the transmission line are sent to the line-inspection maintenance personnel in a form of mobile short messages, and the line-inspection maintenance personnel carry out repair and maintenance.