An onscreen function execution method for a mobile terminal having a touchscreen is provided. The method allows for executing functions of an activated application by a tap on a specific area of the touchscreen. An onscreen function execution method of the present invention includes mapping active regions of the touchscreen to functions of at least one application, displaying an application screen in response to an application activation command and executing, if a tap is detected on one of the active regions, a function mapped to the application activation command. The active regions may include a function execution display region and the applications may comprise a camera application, a music player application, an idle mode screen application and the like. The method allows a user to execute functions of an activated application by tap on the touchscreen.