The invention discloses a wind-induced vibration mode measuring method of a power transmission line based on a machine binocular vision system. The machine binocular vision system comprises a transmission tower lead, a post vibration lead, measuring targets and a binocular identification displacement monitoring system. The measuring targets are arranged in specific positions of the power transmission line, a high-speed camera is used to implement continuous shooting, pictures are transmitted to an image processing computer via a transmission lead, instantaneous lead displacement change is calculated according to change of a distance between the adjacent targets, and a vibration mode of towers is obtained. The method has the advantages of being high in operationality, stability, sampling rate, precision and instantaneity and free of contact, can be used to monitor dynamic displacement and deformation of the transmission tower lead effectively, and thus, provides basis for real-time monitoring researches and operation safety monitoring and evaluation of wind-induced collapse of the transmission towers due to vibration of the transmission tower lead.