The invention discloses a power transmission line tracking method and system. The method comprises the steps of: utilizing a ratio operator to carrying out edge detection on an image, and obtaining an edge binary image; carrying out housh conversion on the binary image, outputting a straight line of a power transmission line, and storing hough space parameters of the currently output straight line of the power transmission line; combined with the hough space parameters of a straight line of the power transmission line, applying particle filtering for successively calculating hough space parameters of each subsequent video frame, carrying out line determination on the straight line of the power transmission line by utilizing a Bayes classifier, and obtaining a determination result indicating whether the straight line of the power transmission line is a right power transmission line. According to the invention, collected continuous video frames are used for carrying out power transmission line tracking, the detection efficiency and accuracy of the power transmission line are improved, and the Bayes classifier is utilized for carrying out line determination on the power transmission line obtained by tracking, so that the detection accuracy of the power transmission line is further improved.