In this paper the method of comprehensive comparative advantage index was mainly adopted to calculate and analyze the national comparative advantage of ten major crops(including rice,wheat,sweet potato,maize,soybean,cole,cotton,ramee,sugarcane and flue-cure tobacco) from Hunan Province from 1991 to 2005.The study result indicated that rice,cole,ramie and flue-cure tobacco from Hunan Province had comparative advantage inside China and soybean,sugarcane,maize and wheat did not have that.At the same time,sever...