Abstract: Disclosed is a three dimensional image display method and some application structures. The three dimensional display method employs one piece of flat mirror to separate an observer's right and left eyes while flipping one image, either right or left, to overlay with another to render a vivid three dimensional image. The method does not need eyeglasses, does not need to see through any optical elements, has no limit to the field of view, and is the most nature method for observers to view a three dimensional image just as to view the real world with naked eyes.