Abstract: Schema matching is one of the research directions of data integration and semantic Web. Its work is to discover correspondence of schema elements using heuristic information. We proposed a new classification of schema matcking based on the way that heuristic information is processed. An overview of composed schema matching was given according to different aggregation methods of schema matching results. Uncertainty is the inherent character of schema matching. We surveyed data models modeling uncertainty of schema matching,and on this basis we introduced uncertain schema matching. At last we prospected the research directions.

Key words: Data integration, Schema matching, Uncertainty