為長久保存數位物件並提供使用，且其真實性、完整性不受質疑，除轉存、轉置、技術模擬、資料封包等方法外，還需要保存後設資料的配合，近年來，國際間已有許多相關研究。本文由數位保存的困境談起，介紹保存後設資料的定義及範疇，並簡介幾個知名的保存後設資料研究計畫，及他們的共同基礎—OAIS參考模型，逐一談及較早期的美國RLG研究、英國Cedars計畫、澳洲國家圖書館保存後設資料項目研究、歐洲Nedlib計畫，及OCLC與RLG合作的研究成果，並比較各研究計畫之結果及特色。最後，本文彙整保存後設資料發展的方向及議題，供國內數位典藏機構參考。

In order to ensure the long-term accessibility, authenticity, and integrity of digitally preserved resources, several approaches including data format replacement, data code displacement, technical emulation, and data package are widely employed. Both data code displacement and technical emulation need the metadata to record the switching history and contextual information of a digital object so that future users may have access to reconstructing or operating the digital object. A number of international researches on metadata preservation have developed on the basis of OAIS. The characteristics and achievements of some of the projects on metadata preservation, such as the Cedars Project of UK and OCLC/RLG working groups, will be introduced and compared in this paper. Finally, the future direction for the development of metadata preservation will also be an issue under discussion.