The method of Fuzzy Preferential Ratio of similarity has been used in the division of regions for introducing and -expanding oil palm plant in Hainan Island. Since it is quite evident that Hainan Island differs greatly from the original or primary oil palm growing areas in climatic conditions, we take Yaxian county, where oil palm growing is the best in China at present, as a fixed sample to show the similarity of climatic conditions in different oil palm growing places to that of Yaxian County. The whole i...