A three-dimensional (3D) display apparatus is provided. The 3D display apparatus includes a display device, a twisted nematic (TN) liquid crystal panel, and a lens unit. The display device is configured to output first polarized lights of an image. The TN liquid crystal panel is coupled to the display device and containing a plurality of controllable pixel display areas to receive the polarized lights with a first polarization direction from the display device. Each pixel display area is capable of being in a first state in which the first polarization direction is transformed into a second polarization direction different from the first polarization direction and a second state in which the first polarization direction is maintained. Further, the lens unit is coupled to the TN liquid crystal panel and is configured to guide the polarized lights with the second polarization direction to pass through and to guide polarized lights with the first polarization direction into predetermined transmitting directions for 3D display.