A three-dimensional (3D) display system is provided. The 3D display system includes a display device and an optical device. The display device is configured to display sets of images with parallax for a 3D display. The optical device has electric-signal-controllable optical parameters and is coupled with the display device. Further, the optical device is configured to enable directional light transmission so as to separate lights of the sets of images into predetermined viewing directions to effect the 3D display.