Abstract: On the basis of both navigational technique and declarative technique of conventional databases, this paper presents a new strategy for object oriented database system （OODBS） queries: Any reference query in OSQL should be pre processed before its actual performance. It is after this query pre processing that the original query can be implemented by means of a mature, single relation query technique of RDBS.And definitions and descriptions regarding OODBS queries are also addressed. The stragey has been proven successful in our distributed OODBS.