A dual standby mode mobile terminal having a single smart card slot and communication mode control method thereof is provided for enabling the mobile terminal to operate in dual standby mode with a single smart card. A dual standby mode mobile terminal includes a first control unit for controlling a first communication mode, a second control unit for controlling a second communication mode, a removable dual mode smart card containing first and second communication mode data, and a buffer for loading the first and second communication mode data. A communication mode control method for the dual standby mode mobile terminal includes loading the first and second communication mode data in the buffer from the dual mode smart card under the control of the first control unit, detecting an event requiring communication mode data provided by the dual mode smart card, determining whether the communication data are any of the first and second communication mode data loaded in the buffer, and executing the event using the communication mode data loaded in the buffer. The dual standby mode mobile terminal and communication mode control method thereof enables the mobile terminal to stand by in two different communication modes (e.g. GSM and CDMA modes) with a single smart card.