A method is adapted for providing privacy to a display device. The display device is adapted to display a normal image that can be viewed in a user area within which a user is situated. The method includes the steps of: a) configuring the display device to generate information of an interference image; b) configuring a display panel of the display device to display the normal image and the interference image; and c) configuring the display device to direct the interference image toward areas outside the user area. Accordingly, the user situated in the user area is able to view the normal image, while a viewer outside the user area is able to view the interference image, thereby achieving a privacy effect.