Disclosed are a method and apparatus for outputting a user interface (UI) event of a 3rd party device in a home network having a server, a client and a control point, the server and the client joining a UI session by using a remote protocol, the control point controlling the server and the client. The method includes (a) receiving by the control point a UI event message from the 3rd party device not joined in the UI session, the UI event message representing change in a state of the 3rd party device, (b) selecting by the control point a target client for processing a UI event, (c) transmitting by the control point an Out-of-session connect action message (OOSConnect Action) requesting connection setup with the 3rd party device to the selected target client, and (d) transmitting by the target client a permission message for the OOSConnect Action to the control point, thereby setting an Out-of-session connection OOSConnect with the 3rd party device and processing the UI event.