The difficulty of data integration is how to solve the problem of heterogeneous semantics. Using ontology’s advantage in semantic integration, this paper designs a data integration frame based on ontology semantic mapping. According to the definition and structure of the ontology concepts, an ontology semantic mapping algorithm is given, which confirms the concepts’ semantic relationship by a comparison between attribute sets, and takes the semantic information of concept names, attributes and correlative concepts into account when the similarity degree is computed. Finally, the ontology semantic mapping is determined by the mapping algorithm of the concepts’ attribute sets and the concepts’ mapping algorithm. Therefore the problem of semantic mapping in data integration is solved properly.