Disclosed are a method and an apparatus for controlling the focus of a projector of a portable terminal when the projector is operated. The method includes projecting screen data by enabling an auto-focusing operation of the projector; capturing the projected screen data through the camera, and detecting a change of a value of the captured screen through a sensor; and when the change of the value is greater than a preset threshold value, temporarily stopping the auto-focusing operation of the projector and projecting the screen data.