The invention relates to a planar object detection method based on a continuous edge characteristic, and belongs to the technical field of machine vision image processing. The method comprises the steps including extracting the continuous edge characteristic, establishing a target contour model, extracting candidate objects based on a Hough transformation idea, screening the candidate objects and realizing accurate positioning. The method is suitable for an industrial scene, and can be used to establish a model of an unknown planar object rapidly and realize object detection. The method needs not to be adjusted for the specific object, and is suitable for different planar objects (as well as objects whose surfaces are planar), and the problem that the university of a present visual system is low is solved to certain extent. The detection precision is higher, the processing speed is high, and certain anti-noise capability is provided.