A method of projecting an image by using a mobile device, the method comprising: determining, as a projection image, an image area displayed on the mobile device, from among an entire image expressing content being replayed or accessed on the mobile device; projecting the projection image and a pointer disposed on the projection image; in response to detecting a change in an inclination or a position of the mobile device: determining whether an amount of change in an inclination or a position, for a preset period of time, of the mobile device exceeds a pre-determined critical value; changing the projection image within the entire image according to the amount of change if the amount of change in the inclination or the position for the preset period of the time exceeds the pre-determined critical value; redetermining a new projection image based on the amount of change in the inclination or the position, the new projection image being moved by an amount of an area corresponding to the amount of change in the inclination or position; and projecting the pointer disposed on the changed projection image disposed on the redetermined new projection image, wherein redetermining the new projection image comprises: predicting a distortion of the changed projection image based on the amount of change in the inclination or the position of the mobile device; and correcting the predicted distortion of the changed projection image. determining, as a projection image, an image area displayed on the mobile device, from among an entire image expressing content being replayed or accessed on the mobile device; projecting the projection image and a pointer disposed on the projection image; in response to detecting a change in an inclination or a position of the mobile device: determining whether an amount of change in an inclination or a position, for a preset period of time, of the mobile device exceeds a pre-determined critical value; changing the projection image within the entire image according to the amount of change if the amount of change in the inclination or the position for the preset period of the time exceeds the pre-determined critical value; redetermining a new projection image based on the amount of change in the inclination or the position, the new projection image being moved by an amount of an area corresponding to the amount of change in the inclination or position; and projecting the pointer disposed on the changed projection image disposed on the redetermined new projection image, determining whether an amount of change in an inclination or a position, for a preset period of time, of the mobile device exceeds a pre-determined critical value; changing the projection image within the entire image according to the amount of change if the amount of change in the inclination or the position for the preset period of the time exceeds the pre-determined critical value; redetermining a new projection image based on the amount of change in the inclination or the position, the new projection image being moved by an amount of an area corresponding to the amount of change in the inclination or position; and projecting the pointer disposed on the changed projection image disposed on the redetermined new projection image, wherein redetermining the new projection image comprises: predicting a distortion of the changed projection image based on the amount of change in the inclination or the position of the mobile device; and correcting the predicted distortion of the changed projection image. predicting a distortion of the changed projection image based on the amount of change in the inclination or the position of the mobile device; and correcting the predicted distortion of the changed projection image.