Abstract: An electronic device includes a display and a processor. The display displays a present application program in a first brightness. When the electronic device in normal-use status receives no user input for a predetermined idle time period, the processor determines whether the present application program is in a half-suspend list. If yes, the processor controls the electronic device to enter a half-suspend status and keep the present application program running, but controls the display to display the present application program in a second brightness, which is less bright than the first brightness. A half-suspend controlling method of the electronic device is also provided.