A method for unlocking screen, a mobile electronic device using the same and a storage medium thereof are disclosed. First, at least two signal input areas on a touch screen of the mobile electronic device are defined. When an input signal is detected within at least one signal input areas, a moving range of a trajectory produced by the input signal is calculated. And the touch screen is unlocked when the moving range reaches the predetermined value. Thus, the present invention provides a user with more virtual manner to close the screen locking function so as to promote the usage convenience of the mobile electronic device.