A method and apparatus for providing security of a mobile terminal in various ways are disclosed. The present invention includes receiving a 1st signal from a mobile communication network via a wireless communication unit, when the display unit is activated, displaying a 1st substitute screen including a password input window on a display unit, inputting a password to the password input window, transmitting the inputted password to the mobile communication network via the wireless communication unit, if a 2nd signal indicating that the password is valid is received from the mobile communication network in response to the transmission, canceling the 1st substitute screen, and if a 3rd signal indicating that the password is not valid is received, maintaining the 1st substitute screen.