An apparatus for outputting an event of a third party device in a home network is provided, which includes a remote user interface (RUI) client taking part in a user interface (UI) session using a universal plug and play (UPnP) remote protocol; an RUI server taking part in the UI session, judging whether the RUI client exists on the home network, storing and transmitting an event message of a third party device that does not take part in the UI session; and an i-box receiving the event message from the RUI server if the RUI client does not exist on the home network, and transmitting the event message to the RUI client existing outside the home network by using an external network.