Abstract: Combined with area information of disaster affected crops in Fujian province for nearly 31 years from 1978 to 2008,and in order to conduct an objective analysis of the disaster and the variation trend of the effect the frost disaster brought to agriculture,the normal information diffusion method of calculation was applied to this research.The results showed that affected area and disaster area caused by frost in Fujian are relatively small,and the inter annual fluctuations of the affected index and the disaster index are relatively consistent.The risk probability of the affected and disaster decreases with the level of disaster risk increased.The risk of affected is greater than the risk of disaster.When averaging the risk of affected and disaster,ie when crop area of affected and disaster caused by frost occupies 2.34% and 1.23% respectively of the total crop area,the risk of affected and disaster is once in 2.6 years and once in 2.3 years respectively.Compared with actual state of the affected and disaster over the years,risk assessment results are more consistent with the actual situation,demonstrating that application of this model is feasible to the risk assessment on natural disasters when lack of information.

Key words: Information diffusion, Frost hazard, Risk assessment