Abstract: The application of machine vision technology in the distance detection of transmission networks can better improve the accuracy of detection.Especially in some important places and harsh environments,machine vision technology can better replace human labor.In this paper,a new distance detection method is proposed combining binocular vision technology and image processing technology.The Laplacian of Gaussian（LOG） algorithm is firstly applied to preprocess the collected images to obtain clear edge information.Then the coordinates of the edge points of the image can be obtained based on the principle of binocular vision stereo reconstruction.Finally the distance formula of the space point is used to calculate the distance set between the edge points of the object and the transmission line.The shortest distance is found out for determining whether the surrounding objects are within a safe distance range.The accuracy of this method satisfies the need of examine of the safe distance between obstacles and surrounding transmission lines.