Based on metadata documents of the multi-source databases,the conceptual model dictionaries were set up to describe the objects,structures and relationships,the methodology dictionaries were set up to constrain and verify data items,and general dictionaries were set up to record and maintain operations of the databases.The data dictionaries extracted and integrated the homologous structures and operations in multi-source geology spatial databases,and interposed a middleware between applications and objects in the database system,aided the universal management of data from different departments.The research showed that application of data dictionary in universal database management could improve the database's efficiency.