Mobile communication terminal apparatus capable of protecting customer information and method thereof

The disclosed mobile communication terminal device possesses two operating modes: master mode and guest mode. Under master mode, all information and functions are available to use; and under guest mode, information and functions supported by the terminal device are restricted. The restricted range can be setup. Through mode switch key, the said master mode and guest mode can be switched at any time so as to protect information of mobile communication terminal user and personal privacy. Moreover, under guest mode, some operations are disabled so as to avoid some troubles happening and inconvenience for user caused by error operation.