The present invention discloses a method for analyzing power transmission tower structure modal through adoption of a binocular vision displacement monitoring system. The binocular vision displacement monitoring system comprises a measurement target, an image collection device, an image processing computer and a wind speed and wind direction measurement device. The method comprises: setting a target at the weak position of a power transmission tower, employing a camera to perform continuous shooting, and transmitting images to an image processing computer through a lead; and calculating the instantaneous changing of the power transmission tower displacement through the image processing software in the computer according to a distance between two adjacent target points so as to obtain the vibration modal of the power transmission tower. The method for analyzing power transmission tower structure modal through adoption of the binocular vision displacement monitoring system has good operability and stability, and is high in sampling rate, high in precision and non-contact, can perform multi-point real-time collection, and realize effective monitoring of the power transmission tower so as to provide the basis for the research of wind-induced collapse of the power transmission tower and optimize the following structure design.