The catastrophe has become a threat to global disaster events, and various countries have different perspective views on catastrophe critical value currently. On the basis of reviewing thecatastrophe critical value, an empirical study on 231 domestic and foreign authoritative and representative sample, we get that agricultural catastrophe is an event with small probability happening and whose real loss is greater than what has been expected. In addition, the cumulative loss is more than withstand object affordability. Thus, agricultural catastrophe is a relative concept,and agricultural catastrophe critical values measurement and quantitative characterization should bebased on the object affordability of the farmers, insurance companies and the government.