Apparatus and method for providing host function in a multi-standby portable terminal

A method for supporting a host function in a multi-standby portable terminal and an apparatus thereof are provided to offer a conference call function through the connection with portable terminals existing in different networks. A method for providing a host function between heterogeneous networks in a multi-standby portable terminal comprises the following steps. The first portable terminal(100) connects a call between the second portable terminal(200) and the third portable terminal(300) which the heterogeneous networks(250, 350). When a voice signal is received from one of the second and third portable terminals, the voice signal is outputted through a speaker. The voice signal loop-backs to the portable terminal which transmits it and a portable terminal existing in the other network.