This paper describes how to explore the organizational culture in a library. The research theory and model are based on Edgar H. Scheins', who is one of the most famous scholars in organizational culture. First, it clarifies the concept of organizational culture. Secondly, the Schein's six dimensions of his basic assumption, which is the core of organizational culture are described and the application of the assumptions in a library is explained, too. Finally, the author concludes that understanding a library's organizational culture is an important issue before design the human resource management system.