Abstract: Based on the historical data of rainstorm and rice yield over the years,the assessment method of yield loss in rice yield was defined.The conception of effective rainfall of rainstorm was proposed the first time in the disaster-causing factors through analyzing the key time and disaster-causing factors of the impact on rice yield.By fully considering the different influence of rainstorm intensity and the disaster resistant capability of rice in different growth stages,it established a loss estimation model for the effects of rainstorm on early rice and middle-late rice yield,and formed a complete set of the loss assessment of the impact of rainstorm disaster on rice yield in Fujian.The rice yield loss in the torrential rain area of Fujian in 2007 was predicted and tested by means of the evaluation model.The results showed that the absolute values of the prediction error of early rice yield loss were between 0.08% and 5.15%,the average error was 2.15%.The absolute values of the prediction error of the middle-late rice were between 0.02% and 3.77%,the average error was 1.9%.The precision was high,so the damage assessment method was feasible.

Key words: Rainstorm, Rice yield, Damage assessment