A 2D/3D image switching display device includes an image display unit and an image switching unit coupled to the image display unit. The image switching unit includes first and second transparent substrates and first and second transparent conducting elements installed on the first and second transparent substrates respectively. An electrochromic layer and an electrolytic layer are formed on the first and second transparent substrates sequentially. The electrochromic layer produce a color change according to the switching status of the image display unit After a stereo image divided into left and right eye images is received by naked eyes, no moire pattern will be produced, so that no additional light shielding device using a parallax barrier is required for displaying stereo images, and the 2D/3D image switching display device can change a light-shielding angle for adjusting a stereo image display according to the viewing angle.