2021 is known as the "first year of the metaverse", which has attracted the attention of the library community to the metacosm, of which the concept and characteristics of the metacosm, the possibility of library integration into the metacosm, the development and innovation of the metacosm-driven library, the value and construction of the metasymonic library, etc., are the main topics of concern and discussion in the library community on the metacosm. The study believes that as a technical concept, the metacosm will drive the reform and innovation of library resources, services, architecture and evaluation, and it will attract libraries to actively integrate into it. We also believe tha the value of metacosmic libraries will appear at multiple levels, and the construction of metacosmic libraries is mainly divided into three stages: digitalization, networking and intelligence.