In order to meet the demand of exchange, share and reuse business knowledge among the different government institutions in e-government, an ontology-based approach to modeling and collaborating e-government business knowledge was proposed. An e-government business ontology (EG- BOnt) was designed. The model of EG-BOnt was described by the IDEF5 graphically. Then the precise syntax and formal semantics of EG-BOnt were defined by OWL language because of its stronger semantics and logic relation expressiveness. Finally, the architecture of e-government knowledge collaboration management platform ...