The present disclosure provides a method for managing voice calls and gateway device. A gateway device according to the embodiment of the present disclosure includes a voice call module for being connected with a landline device and / or a mobile voice device and configured to provide a calling out service to the landline device and / or the mobile voice device; a cellular
session initiation protocol (SIP)
client module for being connected with a
cellular network and configured to process voice signalling in a
cellular network; an IP network SIP
client module for being connected with an IP network and configured to process voice signalling in an IP network; and a voice call selection module configured to, when receiving a calling out from the voice call module, select either the cellular SIP
client module or the IP network SIP client module for the calling out.