An object contour detection method includes: allowing an image sensor to sense respectively a plurality of images of an object by moving a lens with a shallow depth of field at a plurality of positions repeatedly, meanwhile, record the plurality of positions of the lens and the plurality of images one-to-one corresponding to the plurality of positions; removing respectively unclear areas in the plurality of images to obtain a plurality of clear images, and obtaining a plurality of displacement quantities of depth of field depending on a displacement quantity between each two adjacent positions in the plurality of positions; and extending a depth of the front image to reach the corresponding displacement quantity of depth of field and then combine the front image with the rear image in sequence, allowing the plurality of clear images to combine into a stereoscopic image corresponding to the object contour.