Abstract: In this paper, the authors discuss a method for accessing XML data through object oriented database system. They propose rules for mapping XML data to object model and a method to establish OODB schema for XML data. They also give a method to create a temporary DTD by extracting structure information from XML document on the need of schema building. In order to establish efficient access path, the authors put forward a structure index for XML data, and introduce a method of implementing operations based on structure index. Experiments with real life XML documents indicate that this method is effective.