Abstract: A function key control system integrating a function reminder menu, an assistant description menu and a function set-up menu and a controlling method thereof are provided. The controlling method comprises steps of using an embedded controller in an electronic equipment to detect that a first key is activated. The embedded controller transmits a trigger signal to fire up an application program. The application program opens and displays a function reminder menu. The embedded controller detects that a second key is activated and diagnoses a type of the second key. According to the type of the second key, either a function corresponding to the second key is performed or an assistant description menu and a function set-up menu are opened or the application program is terminated.