The Pacific Islands Countries are mainly located in the southern Pacific Ocean，geographically belong to the Oceania region. Generally most of those countries’ economy are underdeveloped. For a long time，the Asian Development Bank has always supported the development of the Pacific Islands Countries in lots of areas，such as infrastructure and public service，by providing loans and co-financings，grants，technical assistance. The Asian Development Bank has assisted to the Pacific Island Countries，on the one hand，because the assistance is closely related to its missions and objectives，on the other hand，due to its largest shareholders’（the United States and Japan）foreign policy and strategic concern. The Asian Development Bank is an important non-governmental organization which plays a significant role in aiding the Pacific island countries. The Asian Development Bank features prominently with the concept，the mechanism and the central areas of assistance.