A new method of three-dimensional(3D) reconstruction using single CCD is proposed. A flat mirror with regular octagonal markers and a single CCD camera are used in the method. Bilaterally symmetrical structure is obtained by utilizing the object in space and its image in the flat mirror based on geometry of bilateral symmetry. A single perspective image of this structure is equivalent to two perspective views of half of the structure. The two halves are projective equivalent in difference of a reflection transformation and the structure is auto-epipolar in the image taken by the camera. Flat mirror is not only a symmetrical plane, but also used as calibration plane. Extrinsic parameters of the camera are calculated by using vanishing point constraint of regular octagonal markers. The validity of the proposed method is proved experimentally and the results of 3D reconstruction are given. The advantages and limitations of this method are summarized. The designed regular octagonal sparse marker is possessed by orthogonality and parallelism at the same time. It is a new solution for online calibration of camera extrinsic parameters.