The joint catalogue is the collection catalogue of libraries and data units in a library system, or in a local, regional, national or several countries; The scope may include participation in all or part of the library's collection, and the form of the collection materials is not limited. The scope and arrangement of the topic are not necessarily the same, but it should be easy to find the collected materials. When the federated catalog is never completed or completed, it always adds new collection records to keep its timeliness.
The joint catalogue can be card-shaped, and new materials can be added at any time. It can be widely distributed in books or microform for easy retrieval, or it can be machine-readable and can be used for online inquiry or printing reports. Its purpose is to mark the collection materials in time, make it convenient for readers to use, and make the resources of all units combine into a whole, share with each other and make full use of them.