The method comprises: before sending the file attribute information to the terminal, the system front end adds the file periodically-updating identity field and the file periodically-updating cycle field into the file download attribute in the file attribute information and valuates them; after receiving the file attribute information, and before starting to download, the terminal executes the following steps: during the file periodically-updating cycle, the system front end cyclically broadcasts the multimedia data broadcast file; after ending the file periodically-updating cycle, both terminal and system front end decide if the time of ending the download comes; if yes, ending the download; otherwise, entering the next update cycle.