In this research, a sample was selected from a public library in Paju city, which operates a regional collaborative library system. They collected data on materials, usage, and acquisition. An analysis of book collection data and usage data was also conducted in order to evaluate the correlation between the usage and acquisition by comparing overlap of purchased materials. As a result, circulations and the interlibrary loan (ILL) borrowing requests were differentiated by topics according to targeted materials, and that these characteristics affect the overlap of purchased materials. The study suggested that public libraries in the region collaborative library system need to consider the paradigm of collection and access when purchasing books.