本文根据我国农业生产状况，将全国分为8个农业区，阐述了各区的主要农业灾害。而后根据粮食产量统计资料和粮食灾损量评估模型，估算了近40年各区的粮食灾损量和全国粮食灾损量，并分析了我国粮食灾损量的时空分布状况。

Grain loss caused by natural disasters in China’s eight agricultural regions during the period 1950～1990 is estimated by the equation:Y_d=Y_t-1 +(y^_p-y_t-1 )S_t+y_t(S_t-S_t-1 )-Y_twhere Y_d is the grain loss due to natural disasters, y_tis grain production per ha in yeart, S_t is planting area in year t, Y_t is the amount of production in yeart , and y^_pis calculated grain production per ha including y^_tand y_e as listed respectively in Tables 3 and 7. After the situations of agricultural production, irrigation, agricultural input and natural disasters are discussed, the estimated grain loss for the eight agricultural regions in 1950～1990 is presented. The estimation shows that the average yearly grain loss due to natural disasters is 34 billion kg, or 11 6% of the yield. The time series for the percentage change is given in Figure 2, which shows a decreasing trend since the early 1960s. The regional patterns of the percentages of loss vary. Northeast China has had the most grain loss, followed by North China and then South China.