Abstract: Using optimum situational concept and its countermeasure method in measure-taking for grey situations,three amounts of climatic decrement of crop yield,loss of output by value per unit area and occurrence rate of disaster are established for analyses of types of damages caused on principal Guangxi crops by drought,flood or cold.It forms a multipurpose grey situation with event items(A=a_i,i=1,2,3,....,n) for types of disaster and countermeasure item(B=b_j,j=1,2,3,....,8) for the eight prefectures of Guangxi.The situation is optimized before presenting an explicit result of countermeasure for the prefectures.