Abstract: With the development of E-Government informationization, the traditional information sharing mode limit the exchange between various government departments. This paper introduces the current heterogeneous data integration mode, proposes integration mode based on hybrid ontology, and describes the function of each part. This mode can effectively shield the heterogeneity of data and protect the independence of each system. This paper describes the methods of constructing domain ontology and ontology mapping, and illustrates the building process of the domain ontology.