TeSeIn thin film is a kind of reversible phase change recording medium. Two kinds of TeSeIn thin films were prepared by thermal evaporation and magnebron spu btering methods respectively. Micromorphology and microstruoture of TeSeIn thin film were studied by TEM method. Using AES-PRO analysis, TeSeln thin film composition depth profile given and the diffusion profile of the interface between TeSeIn thin film and ZnS matching layer are given. The chemical shifts of binding energy of inner electron of Te, Se and In element in TeSeIn thin film are given by X PS measurement. A method for preparing multi-tjomponent phase ohange recording thin film with high quality and high stability is discussed.