The present invention discloses a multimedia message system, which includes: aSP; a Multimedia Message Service Center (MMSC), which is configured to receive, store and send multimedia messages; and a Multimedia Message Service Gateway (MMSG) connecting with at least one MMSC and the SP belonging to the MMSG respectively, which serves to authenticate the SP and a user in the multimedia message and a provided service, and to send the multimedia messages from the SP or the MMSC. And the present invention provides three methods for sending multimedia messages. The system and methods provided by the present invention can lower the load of the MMSC and enhance the security of the MMSC.