Abstract: Aim Enhancing acquiring knowledge capability of the expert system, especially from database Methods The combination methods of expert systems with databases were analyzed, including their benefits and shortcomings, two combination methods were implemented for BITAI EST expert system tools Results The interactive capability of expert system and database is enhanced It brings expert systems great convenience for acquiring knowledge from databases, and it becomes easier for database users to use expert systems Conclusion It provides direct and effective method for developing practical expert systems which are based on database