The function of reader service is to help the patron to use the information effectively. Reference interview is a communication process that occurs between a patron and a librarian. While patron inquiries and librarian responses, the communication is interactive and interdependent. Librarian should have the skills of interpersonal communication to achieve the goal of reader services. The purpose of this paper is to investigate the communication between patron and librarian. First, it discusses the theory, the definition, the objective of reference interview, issues of reference interview and communication barriers. Then, it examines the theory of interpersonal communication and the skills used in reference interview. Last, the author suggests that in order to provide proper assistance, library should reinforce and develop librarians' communication skills and reduce their workload.