A mobile electronic device, a method for entering a screen lock state and a recording medium thereof are provided. In the present method, an input signal is received through a touch panel of the mobile electronic device. Then, a movement track of the input signal is obtained if a starting point of the input signal is located in a non-display area of the touch panel, and a vertical displacement of the input signal is calculated if the movement track contains a specific direction. Finally, a screen lock frame is dragged and displayed, and the mobile electronic device is switched to the screen lock state if the displacement reaches a predetermined value. Thereby, an intuitional way for locking the screen is provided, and accordingly, the convenience in operating the mobile electronic device is improved.