The method of borrowing introduction media can only be applied to small-scale libraries. Larger libraries usually use online lending. Firstly, the CD attached with books is made into a CD image file and stored in the server, and the CD attached with books is downloaded through CD retrieval. For early audio files, tapes or audio CDs were usually used. These resources can be converted into MP3 file format, which is convenient for saving storage space and providing convenience for use.