The invention discloses a mobile telephone and a data processing method thereof. The data processing method comprises the following steps of: reading the identity of a sub subscriber identity module (SIM) card to judge whether the sub SIM card is locked if the sub SIM card is locked, judging whether to reproduce data on the sub SIM card according to the subscriber option and if the subscriber option is to reproduce the data on the sub SIM card, reproducing the data on the sub SIM card to the mobile telephone, a master SIM card of the mobile telephone, or both the mobile telephone and the master SIM card thereof. According to the mobile telephone and the data processing method thereof, data such as the telephone directory and the like on the sub SIM card can be reproduced to the mobile telephone or the master SIM card of the mobile telephone, thus well solving the problem that because the sub SIM card is locked, the subscriber can not call or send short messages by the telephone directory on the sub SIM card, greatly facilitating use of the subscriber, and being conductive to popularization of business of a mobile operator.
