This paper is a result of interdisciplinary research between natural and social science．Evidences of more rapid development in the loess plateau than in the Yangtze delta in ancient time are given．It is suggested that this might be due to the fact that Holocene climate warming had different effect on the development of the loess plateau and the Yangtze delta．
Finally，causes of three great population migration of the Han People from north China to the lower Yangtze valley are elucidated．The ro1e of three great population migration in rapid economic development of the Yangtze delta since the 7th century is also briefly discussed．