Digital twin technology provides a new strategy and method for the realization of the integration of library full cycle management and Information Physics. This paper puts forward the five-dimensional model of digital twin library, analyzes its operation mechanism, architecture, key technology, collaborative driving framework and digital twin model construction around the concept of full cycle management, and analyzes the corresponding application situation on the basis of theory. The research shows that the digital twin library is mainly composed of five parts: the physical entity of the library, the digital twin model, the digital twin service system, the connection between the twin big data and each part; its full cycle management is mainly composed of three parts: the life cycle of knowledge service, the cycle of digital twin model and the cycle of knowledge service content.