A communication method and apparatus of a dual standby mode mobile terminal for improving the emission performance are provided. The mobile terminal includes a master switch for connecting a master antenna to a master Radio Frequency (RF) unit for communication with a first network, a slave switch for connecting a slave antenna to a slave RF unit for communication with a second network, a slave control unit for controlling communication with the second network and for detecting attachment of a slave Subscriber Identity Module (SIM), and a master control unit for controlling communication with the first network, for detecting attachment of a master SIM, and for controlling the master and slave switches to establish/release either the connection between the master antenna and the master RF unit or the connection between the slave antenna and the slave RF unit.