Highly networked secondary system in smart substation makes its physical structure unclear, and it is inconvenient for maintenance. The appropriate maintenance-protection-rule database is designed to significantly improve efficiency and reliability of maintenance and become basis for computer-aided analysis. The characteristics of maintenance rules is analyzed, which derives the design of maintenance protection rules database structure, including maintenance rule code data table and equipment maintenance rule mapping code data table, with their fields detail design. The database can be applied in storage for rules of optical operations and strip operations in smart substation maintenance protection, and provides interfaces for other analysis software.