Abstract: Ontology is used to solve the problem of schema semantic discrepancy in the information integration system.To solve the problem of data value type semantic discrepancy in the information integration system,a method of query processing mechanism is designed.Query requests a semantic analyzing module and a global query processing module to process the case of homograph and thesaurus.A Sub-query localization processing module processes cass caused by different measure unit.Redundancy discarding module processes case caused by error of redundancy data.These three modules fulfill the query together and they are able to solve the problem of data value type semantic discrepancy.