Disclosed are a mobile terminal capable of implementing an always-on function with a lower power, based on a motion, and a motion-based low power implementing method thereof. The method includes sensing a motion of a user by using an acceleration sensor in a low-power always-on that only the acceleration sensor is activated; a selectively activating an always-on function according to the sensed motion and deactivating the always-on function when no motion is sensed in an always-on state and automatically entering to the low-power always-on function.