8. A wearable electronic device for controlling a function by using voice recognition, comprising: a touch screen; a sensor; and a processor configured to: control the sensor to detect a predetermined gesture for activating a voice recognition function of the wearable device, wherein the wearable electronic device is worn on a wrist of a user, drive a timer for calculating a time period from an instance when the predetermined gesture is detected, recognize eyeballs of the user through one or more cameras of the wearable electronic device, activate the touch screen and the voice recognition function when the time period calculated by the driven timer exceeds a predetermined time period and the eyeballs of the user are recognized, control the touch screen to display a screen of the activated voice recognition function for receiving a voice input to control the voice recognition function of the wearable electronic device, receive the voice input through the activated voice recognition function, determine whether one or more functions executable by the received voice input include a user's personal information of the wearable electronic device, if the one or more functions executable based on the voice input do not include the user's personal information, analyze the voice input by using the activated voice recognition function, and execute a function that does not include the user's personal information, based on the voice input, and if the one or more functions executable based on the voice input include the user's personal information of the wearable electronic device, output, through the activated touch screen, a message indicating that the one or more functions including the user's personal information are not executable, wherein the output message includes a function list of one or more functions that are executable by at least one voice input different from the received voice input and do not include the user's personal information.
8. A wearable electronic device for controlling a function by using voice recognition, comprising: a touch screen; a sensor; and a processor configured to: control the sensor to detect a predetermined gesture for activating a voice recognition function of the wearable device, wherein the wearable electronic device is worn on a wrist of a user, drive a timer for calculating a time period from an instance when the predetermined gesture is detected, recognize eyeballs of the user through one or more cameras of the wearable electronic device, activate the touch screen and the voice recognition function when the time period calculated by the driven timer exceeds a predetermined time period and the eyeballs of the user are recognized, control the touch screen to display a screen of the activated voice recognition function for receiving a voice input to control the voice recognition function of the wearable electronic device, receive the voice input through the activated voice recognition function, determine whether one or more functions executable by the received voice input include a user's personal information of the wearable electronic device, if the one or more functions executable based on the voice input do not include the user's personal information, analyze the voice input by using the activated voice recognition function, and execute a function that does not include the user's personal information, based on the voice input, and if the one or more functions executable based on the voice input include the user's personal information of the wearable electronic device, output, through the activated touch screen, a message indicating that the one or more functions including the user's personal information are not executable, wherein the output message includes a function list of one or more functions that are executable by at least one voice input different from the received voice input and do not include the user's personal information. 9. The wearable electronic device of claim 8 , wherein the sensor is further configured to detect whether the predetermined gesture is a movement raising the touch screen of the wearable electronic device making an altitude of the wearable electronic device higher.