Abstract: In order to construct high-powered deductive database system, the authors present a design scheme to construct a deductive database system based on SQL server relationship database and adding a rule process layer on it. The system is composed of language analysis unit, rule management, agreement maintenance unit and recursion query reasoning machine, etc. Whether the design thought of rule maintenance unit, the algorithm of maintaining integrity and some resolution schemes to the key problems, or the design principle of reasoning machine which can realize recursion query, the algorithm of recursion query and its optimization technology during its realization are all discussed detailedly. Rule reasoning can deduce unknown information from known fact. Integrity maintenance is used to express all kinds of restriction relationship between rules so that in coordinated or in compatible information can be avoided. The reasoning module can implement deductive reasoning function correctly. Particularly it is effective to realize linear recursion query.