An apparatus and method set up an interface in a mobile terminal. The method includes: storing an interface setup application including customized data unique to countries and operators; determining whether a Subscriber Identity Module (SIM) card is inserted into the mobile terminal when the mobile terminal is powered on; detecting a Mobile Country Code (MCC) and a Mobile Network Code (MNC) included in the SIM card, if the SIM card is inserted into the mobile terminal; executing the interface setup application and searching for customized data corresponding to the detected MCC and MNC from among the customized data unique to countries and operators; and installing an interface of the mobile terminal based on the searched customized data.