This study aims to present an improved model of the organizational structure for national university libraries in Korea. The results of this study are as follows : 1. A small scale library serving to a population of less than 15,000 should be organized with a staff of 50-60 persons, 3 departments and 10-13 sections (3 departments and 9-12 sections of central library + 1 section of branch library) 2. A medium scale library serving to 15,000-25,000 population should be organized with a staff of 80-120 persons, an associate librarian, 5-6 departments and 18-21 sections (4-5 departments and 15-18 sections of central library + 1 department and 3 sections of branch library) 3. A large scale library serving to a population of over 25,000 should be organized with a staff of 140-170 persons, an associate librarian, 7-8 departments and 25-28 sections (5-6 department and 20-21 sections of central library + 2 departments and 6 sections of branch libraries)