A method for listening to signal tone from a called party by a calling party during network interworking. When the media gateway control unit receives an Address Complete message or Call Progress message from the circuit domain network, the media gateway control unit instructs a media gateway to open a media stream channel. If the received message carries an indicator indicating the called party is free, the media gateway control unit sends a Ringing response message to the packet core network; if the received message does not carry a indicator indicating the called party is free, the media gateway control unit sends a response message carrying indicator of failed call but successful media stream setup or a response message indicating failed call but successful media stream setup to the packet core network. With the method according to the embodiments of the present invention, the calling party may hear ring-back tone indicating successful call, or signal tone or voice announcement indicating failed call.