A network apparatus for interconnecting heterogeneous networks and an interconnecting method thereof. The network apparatus includes a communicator configured to communicate with a heterogeneous network apparatus using the same frequency band, to communicate with the heterogeneous network apparatus through a gateway in a first communication mode, and to perform direct two-way communication with the heterogeneous network apparatus in a second communication mode; and a processor configured to determine a signal received through the communicator, and to determine a communication mode with the heterogeneous communication network.