An electronic device having a 3-D image projection mechanism is provided. The electronic device comprises a display panel, a processing module, a projection screen and at least two micro projectors. The display panel is formed on a main body of the electronic device to display a 2-D display frame. The processing module determines whether a 3-D display request is received and generates a 3-D display command when the 3-D display request is received. The projection screen is formed according to the 3-D display command and is substantially vertical to the display panel, in which a light refractive rate of the projection screen is different from that of the air around the projection screen. The micro projectors are disposed in a circumference of the display panel and project image on the projection screen according to the 3-D display command such that a 3-D display frame is formed thereon.