Hybrid library is the basic orientation of the present development library. Along with the fast growth of digitalized resources, it is extremely essential to set up a storage system which can meet the need of visiting mass storage and sharing backups. Based on the comparison of the main features of three storage systems (DAS, NAS and SAN) in terms of its notion of designing, connection protocol, style of management and its security, this paper focuses on the situation of the application of centralized management of data mainly constructed on the basis of SAN, tiered storage, as well as the storage system with good safety and strong extensibility in North China Institute of Science & Technology(NCIST).