本文研究目的在探討國際上現有metadata registries的設計與發展，以達成metadata標準相關資訊的再利用與互通性。本文採取個案研究法，以數位圖書館metadata為範圍，選取12個研究樣本進行分析。本文研究發現主要有五項：第一「多數metadata registries (MDRs)已臻至機讀的階段。第二，涵蓋標準數量上有單一與多數兩種。第三，描述對象除了以典藏品為主外，也擴及至人與機構；資訊單元（information granularity）主要包含標準、元素與控制詞彙三個層級。第四，所有MDRs皆為metadata元素間的關係加以標引，只有一些針對標準與元素間的關係予以建立，甚至展延至控制詞彙，而這些MDRs通常不採用用ISO/IEC 11179。第五，發展MDRs有兩大取向，一是採取資料元素方式，通常採用ISO，資料描述十分詳盡；二是採取metadata元素方式，資料描述十分簡易。

　　　　　How to reuse and interoperate the information between various metadata standards becomes an important issue for digital library projects and metadata registries (MDRs) are employed as a workable approach around the world. This paper aims to take a revive on current development of MDRs, by adopted case study as research methodology to examine twelve case. Consequently, five findings are offered in the following:1.most MDRs can be generalized into machine readable MDRs. 2.Some MDRs include elements from a single standard, and some from multiple ones. 3.MDRs focus on cultural heritage objects, but now has been expanded to include institutes and users. Information granularity that MDRs handle is generalized into metadata standard, element and encoded scheme. 4.Relationships between elements are common to all practices, but relationships between standards, elements and encoded schemes are not applied to all. 5.The approach of MDRs description is toward two types: data elements and metadata elements. The former one has a preference for comprehensive description, and the latter one is toward appropriate description for practical requirements and is separated into various identities instead of all in one.