Provided is a method and system for streaming multimedia data between hetero UPnP networks configured of a private network. The method comprises establishing a communication channel with a relay peer; establishing a virtual communication channel with a specific extensible home connector selected from a plurality of extensible home connectors connected with the relay peer; searching multimedia data to play from multimedia data in the specific extensible home connector which exists on the UPnP network through the virtual communication channel; establishing a communication environment through the UPnP internet gateway of the specific extensible home connector in case of demanding play of the searched multimedia data; and receiving multimedia data from the specific extensible home connector through the communication environment.