A system for interfacing external data to IPTV and a method of the same are provided, which register unique numbers of mobile phones, other data communication devices and IPTVs in conjunction with an external data transmission server in advance and have an SMS server, a mobile communication company's server and a mail server and external data transmission server linked with one another, and which transmits at least one of text, moving image data, and still image data to a desired mobile phone or IPTV according to user's setting for its output. This present invention can interface external data received by various data communication devices such as a mobile phone, an email server, and a mobile communication company's server to IPTV for its output onto the screen according user's setting, and establishes an output time of the external data in advance by a user to output it at a time of high concentration.