The invention provides a method for streaming media transmission. The method comprises the steps that a CDN (content delivery network) server receives a play request from a media player for requesting a media description file, a media fragmentation corresponding to the play request in cached media fragmentations is determined, a media description file is generated according to description information carried by the determined media fragmentation, and the generated media description file is sent to the media player; and when a play request from the media player for requesting a media fragmentation is received, a media fragmentation corresponding to the play request in the cached media fragmentations is determined, description information carried by the determined media fragmentation is deleted, and the determined media fragmentation is sent to the media player to play. Based on the same invention concept, the invention further provides a device and a system for streaming media transmission, thereby not only being capable of reducing CDN load sharing, but also being capable of dynamically generating the media description file which is suitable for the media player to use.