A method and apparatus is provided for controlling a dual display using a Red, Green and Blue (RGB) interface in a mobile terminal with a projector module, in which the projector module expends a high-resolution image and projects the expended image to the outside, a display displays a menu image for operation of the projector module, an image processor has a first buffer assigned to the display for data transmission to the display, and a second buffer assigned to the projector module for data transmission to the projector module, and a controller transmits image data to the first and second buffers, and outputs control signals for activating both or a selected one of the first and second buffers, depending on selection of a display mode.