1. A mobile communication apparatus comprising: an anti-theft control circuit comprising: a SIM-card-detection module detecting whether a first SIM card is replaced by a second SIM card; and an information management module storing a predetermined user contact information, and a user personal database comprising at least one of a phonebook database, a schedule database, and an e-mail database; a transmission control circuit transmitting data and signal; wherein if the SIM-cared-detection module detects that the first SIM card is replaced by the second SIM card, the transmission control circuit sends out, according to the predetermined user contact information, personal data of an original owner stored in the phonebook database, the schedule database, or the e-mail database of the information management module when the first SIM card is not yet replaced by the second SIM card, thereby enabling the original owner to get back the personal data of the phonebook database, the schedule database, or the e-mail database stored in the information management module when the first SIM card is not yet replaced by the second SIM card, wherein the predetermined user contact information is contact information predetermined by the original owner; and a security module, wherein after the personal data are sent out, the security module waits for a confirmation signal to confirm that the record or records have been transmitted according to the predetermined user contact information successfully.