Metadata is an important part of Open Data Initiative across the world. Based on W3C metadata standard DCAT（Data Catalog Vocabulary）, American Project Open Data (POD) and DCAT-AP of EU, this paper analyzes the achievements and characteristics of the metadata in the United States, European Union and Ireland. By comparing metadata schemas of Chinese local governments such as Beijing, Shanghai and Zhejiang, this paper points out that the metadata construction of China's OGD should be strengthened from aspects of policy support, legal protection, system improvement and adoption of semantic technology so as to overcome the drawback in the normalization, standardization and interoperability.