Currently, knowledge-based sharing and service system has been a hot issue and knowledge fusion, especially for implicit knowledge discovery, becomes the core of knowledge processing and optimization in the system. In the research, a knowledge fusion framework based on agricultural ontology and fusion rules was pro- posed, including knowledge extraction, clearing and annotation modules based on a- gricultural ontology, fusion rule construction, choosing and evaluation modules based on agricultural ontology and knowledge fusion module for users' demands. Finally, the significance of the framework to system of agricultural knowledge services was proved with the help of a case.