Using the methods of center of gravity, population density, relative rate of change and spatial measurement, this article studies the evolution of population distribution pattern and its drivers in the Yangtze River Delta. The results show that: 1) the change in the migration direction of the population center of gravity from 2000 to 2018 characterized the transformation of population distribution pattern, and the slower migration speed indicates the transition of regional development to a steady state; 2) On the basis of relatively stable regional differences in population density distribution, the spatiotemporal evolution has changed from the significant increase in Shanghai and southern Jiangsu from 2000 to 2012 and the decline in some cities in middle Jiangsu, northern Jiangsu and Anhui, to the rapid growth of population in some underdeveloped cities from 2012 to 2018; 3) Spatial econometric regression shows that under the "Matthew effect" of population agglomeration, the changes of drivers are mainly manifested in the strengthening of market forces and the weakening of government influence. On the other hand, the promotion of regional integration also brings about the enhancement of spatial spillover effect.
