Abstract-This paper introduces the current practices of building the network of institutional repositories in Chinese Academy of Sciences (CAS), which called CAS IR Grid. Firstly, it presents and discusses its architecture. Then it discusses issues related to its implementation and promotion activities, which covers mainly the development of IR software package based on open source software DSpace, establishment of longterm working mechanism of promotion IR service, achievements of spreading activities, and the development of CAS IR Grid service portal. Finally, it puts forward some considerations on future development of CAS IR Grid.