Abstract: [Purpose/Significance] Mary W. Plummer was an important figure in the history of American librarianship and an active promoter of international exchange of library science knowledge.There are few studies about the communication between Plummer and the European library community and her subsequent dissemination of European library science in American. [Design/Methodology] Using the historical research method, this paper examined Plummer's two trips to Europe in 1890 and 1894, especially her reflection on the European librarianship from the perspective of an "observer", and the Second-Year Course centered on history and bibliography established by Pratt Institute in 1896. [Findings/Conclusion] The Second-Year Course focused on the history of book and printing, the cataloguing of incunabula,paleography and other subjects aimed at cultivating "learned librarians", which reflected the distinctive European imprint in the curriculum, teachers, students training and other aspects. The program was a concentrated reflection of the influence of the Plummer's tours of Europe, which promoted the westward spread of the classical European library science to the United States. [Originality/Value] Unlike previous studies that paid more attention to the influence of American library science as an "exporter" to other countries, this study considers American library science as an "importer", and examines the external influence of other countries on American library science, which helps to reveal the process of international library science knowledge exchange more comprehensively.

Key words: Mary W. Plummer, Pratt Institute, History of library science exchange, Comparative librarianship