为检验已订的洪水灾情等级标准的合理性 ,提出了一种新的洪水灾情等级模型 -逻辑斯谛曲线 (LOG)模型 ,它的灾级是连续的实数值。根据 LOG模型参数值可以分析各灾情指标值对灾级的影响程度 ,从而检验原订灾级标准的合理性 ;并给出了基于实码遗传算法的 LOG建模的实施方案。实例研究说明了这套方案是实用和通用的 ,在其它灾情等级评估中也具有广泛的应用价值 In order to verify the rationality of the existing flood disaster grade standard, a new logistic flood logistic model (Logistic Curve Model) is proposed, whose disaster level is a continuous real number. According to the parameters of LOG model, we can analyze the impact degree of each disaster index value on the disaster level, so as to verify the rationality of the original disaster-prevention standards. And the implementation scheme of LOG modeling based on real-coded genetic algorithm is given. The case study shows that the scheme is practical and universal, and has extensive application value in other disaster level assessment