Collecting is its own basic task of museum and the method of collecting includes purchase, donation, entrustment, exchange and loan and borrows. The entrustment of cultural property(CP), though some museum professionals advocate the effectiveness of it, has not been made full use in Korean museums. It results from the lack of people’s awareness of CP entrustment system and inactive collection policy of museum professionals absorbed in collecting CP through purchase and donation. However, the CP entrustment system needs to be used for the diversity of collections and flexibility of collection policy. Thereby, museum can react quickly and properly to its operating environment which is rapidly changing and complicated. This study aimed at entrustment which means that an original owner has the ownership of the CP while museum has the right of management, to use or of possession for the preservation, management, research and utilization of the CP. This system has the importance because it can compensate the limitation of purchase and donation of CP, reduce the burden of the preservation and management of CP from individuals and enhance the enjoyment right of CP of people. Thus, this study considers the concept and significance of the CP entrustment system. Further, it analyzes the current status of old book entrusted and its utilization of Korean Studies Advancement Center which carries out the variety of business including research, education, exhibition, etc. with entrusted CP. Consequently, it suggests some ways to activate the CP entrustment system in museums.