The invention discloses a method and a system for sharing stream media data, and a stream media node. The method comprises that: the stream media node reports state information per se and queries the state information about other stream media nodes; and the stream media node downloads and/or calls stream media data that the stream media node does not have from the other stream media nodes. The method, the system and the stream media node of the invention, through data sharing among the stream media nodes, ensure that the data of downloading users can be provided for online play users and the data of the online play users also can be provided for the downloading users, so the rate of data sharing among the users can be increased, and the bandwidth load of a server is reduced.