A method for an electric device to take a panoramic photograph is provided and the method includes following steps. A first image is captured. A first line is displayed on a preview window. A first graphical object and a second graphical object are displayed on the first line. Posture information of the electric device is obtained. The second graphical object is moved along the first line according to the posture information. It is determined if the electric device is panned horizontally or tilted vertically according to the first line. A second image is captured if the second graphical object reaches the first graphical object and the electric device is panned horizontally or tilted vertically. The panoramic photograph is generated according to the first image and the second image. Accordingly, a user obtains a panoramic photograph easily.