Abstract: The author considers that agricultural ecology exhibits a strong integrative characteristic, deals with a wide range of disciplines and has close relationship with agriculture. Agriculture itself is an ecosystem, and also an enterprise of ecology. Therefore, agricnltural ecology should be a branch of ecology which mainly studies the ecology of agricultural system. The traditional agriculture all over the worlld possesses a broad ecological rationality, and the mechanized intensive agriculture in western countries has exposed many serious ecological problems. The agricultural modernization of our conutry must be established on the basis of traditional organo-agriculture to develop ecological agriculture.With the above mentioned viewpoint of agricultural ecology, the author reviews the history of our traditional organo-agriculture and its development in the world, and especially points out thetransformation of traditional organo-agriculture——inorganic agriculture——organo-agriculture in Japanand the development of organo-agriculture in Europe and America. At the end of this paper, the author indicates the potential risk of our agriculture’s following the same old disastrous road of Japan.