A service implementing method and apparatus according to an ultraviolet (UV) index in a mobile terminal provides diverse information and services according to the UV index detected by the mobile terminal having a UV sensor mounted thereon. The service implementing method and apparatus includes switching over to a UV alarm function mode when an alarm function is selected in a UV management mode, setting a predetermined time interval for informing a user of the UV index when an alarm interval is selected in the UV alarm function mode. The service implementing method and apparatus further includes setting a specified time for informing the user of the UV index when an alarm time is selected in the UV alarm function mode, and setting avatars or alarm sounds for informing the user of the UV index according to the set time when an alarm method is selected in the UV alarm function mode.