Abstract: With the rapid economic and social development, population distribution among cities in the Changjiang River Delta has undergone significant changes. Population mobility and migration has come into being the most concentrated contradictions with respect to the population development of the cities in the Changjiang River Delta. Using the methods of density analysis, uneven index, gravity centre analysis and shift-share analysis, this paper studies the characteristics and law of the population distribution evolution in the Changjiang River Delta since the beginning of the reform and open-up of China, and furthermore, sums up to the following four points: First, the population evolution of the cities in the Changjiang River Delta shows different characters in three periods of the year 1980-1990, 1990-1997, 1997-2003. In the first period, the population growth shift is very large, and population distribution is centralized quickly. In the second period, the population uneven index and the population growth shift among the cities are decreased, but the population growth shift among six great regions is increased obviously. In the third period, the population distribution among the cities is centralized, and the shift extent of the population growth is increased. Because the population growth shift among the cities in the south of the Changjiang River is higher than that among the cities in the north of the Yangtze River, the overall population distribution center moves southward. The population growth shifts among the regions on each level are different, the regions’ level is higher, the population growth shift is lower, and the population distribution is inclined to more stable. Since 1990, on the condition of the market economy, although competition to attract the population, especially the high quality population, is very heat among the cities in the Changjiang River Delta, the difference of the population growth speeds of these cities is decreased and the centralization of population distribution comes down. Because of the variety of the position and function in the whole region, the traffic condition, and the level of the economic and social development, etc., Shanghai City, the capitals of Jiangsu and Zhejiang Province get more population growth shift in the study period, and the population is continuously centralized to these cities in this period. Anyway, since the beginning of the reform and open-up of China, the distribution of population among the cities in the region of the Changjiang River Delta has come through the visible change, which are mainly droved by the economic and social development, and it is also significantly affected by the policy of the regional population management.