With economic globalization and market-oriented agricultural economy, the impact factors of agricultural risks become more complicated. As a variety of factors intertwine together, the traditional Expert System is difficult to identify and manage agricultural risks, which greatly hampers the process of agricultural risk management. To overcome this problem, we introduce the ontology theory. By constructing agricultural risk ontology and agricultural risk strategy ontology, we can resolve the problem of agricultural risk’s description and identification, and improve the efficiency and reliability of agricultural risk management. In this paper, we introduce the domain ontology theory to the field of agricultural risk management, and describe the basic process of the domain ontology-based agricultural risk management. And then, we propose a framework of ontology-based agricultural risk management and specifically introduce each module in the framework. Meanwhile, based on the method of building ontology, this article constructs the basic frame of the agricultural risk ontology. Finally, to take the drought risk for example, the paper analyses the implementation process and technologies of the domain ontology-based agricultural risk management.