An unassisted stereoscopic display device using a directional backlight structure to produce a stereographic display effect. According to a time-division principle, the display device alternately displays left and right images viewed by the left and right eyes of a viewer. A video field synchronization time sequence is used to control an on-off time sequence of light-emitting units of the directional backlight structure, and when the left image is displayed, only the light-emitting unit corresponding to the left eye of the viewer is lightened, and when the right image is displayed, only the light-emitting unit corresponding to the right eye of the viewer is lightened, such that the left eye of the viewer can only view the left image and the right eye thereof can only view the right image. Binocular parallax images are fused to form a stereoscopic image without a loss of resolution.