The development and cooperation between international organizations are related to the overall international development situation. The International Federation of Library Associations and Institutions (IFLA) and the United Nations Educational, Scientific and Cultural Organization (UNESCO) are representatives of international professional organizations and the international community, with a long history of cooperation. Analyzing and understanding their cooperation process can provide reference and suggestions for the development of the library industry and the international community. This article focuses on analyzing the important events between IFLA and UNESCO at different stages over the past 75 years through extensive literature research. The research findings indicate that the cooperation between IFLA and UNESCO promotes international cooperation and win-win outcomes, promotes sustainable development of international culture, and promotes the development of a diverse world.