Ontology based semantic information integration can solve the schematic heterogeneity among distributed data sources, but can not solve context heterogeneity which widely exists. Because context semantics is implicit which can not be captured and understood by information integration systems. To solve context heterogeneity, firstly a formal context presentation to describe the implicit semantics formally is introduced. Then, a flexible, adaptive and scalable context conversion method based on the format’s metadata representation is proposed to resolve format heterogeneity, which is one of the context heterogeneities. This method avoids the shortcomings of the existing methods which need to define numerous mappings repeatedly.