The invention discloses a real-time rectification algorithm for a circular instrument of a transformer station, and the algorithm comprises the steps: carrying out the preprocessing of an equipment instrument image, obtaining an edge image through Canny edge detection, carrying out the Hough ellipse detection according to the edge image, obtaining the regional features of inclined equipment which comprise the axis length, focusing point and inclination angle, obtaining a rotation matrix according to the corresponding relation of the regional features through perspective transformation, carrying out the rectification of the equipment image, and obtaining a front view of the target equipment image. The algorithm can achieve the image correction, is simple, is high in speed, is high in robustness, and can be used on an intelligent routing inspection robot of the transformer station.