The invention discloses a substation construction field three-dimensional security protection method. The method includes the following steps that: two cameras are required to be installed in a substation construction field, and a region required to be protected has image intersections in the images of the two cameras; video images are acquired through a front-end camera; each camera compresses acquired video images and decomposes the video images into YUV images required by intelligent analysis; each camera converts the YUV images into RGB images; each camera compares a next frame of image with a last frame of image, and updates background environment in real time through utilizing self-learning, so as to extract a target object from the background environment; the pixel points of the extracted target object in each camera are calculated, and three-dimensional security protection can be realized according to the intersection positions of the target object in the two images and the angles of the cameras. With the method of the invention adopted, substation construction field three-dimensional security protection situations can be conveniently identified in time.