Since China became an aging society in 2000, the regional inequality of population aging has been highlighted, and the phenomenon of "aging before getting rich" has gradually become a core issue in China's coordinated socioeconomic development. This paper aims to comprehensively assess the spatial differences and driving forces of China's population aging through two-stage nested Theil decomposition, ESDA, and spatial econometric models. Empirical results show that spatial differences in population aging were evident at different spatial scales, and the distribution gradually decreased from east to west, showing a positive spatial correlation of similar value aggregation. Moreover, China's population aging was determined by the demographic, socioeconomic, and natural environment, and there are different leading factors in different regions. The demographic aspects played a decisive role and had a direct influence, while the socioeconomic and natural environment indirectly affected population aging through demographic factors and became the root cause of regional differences in population aging. These findings provide an empirical basis for establishing a cooperative mechanism and formulating a targeted response to the problem of population aging in various regions in China.Sustainability 2019, 11, 5959 2 of 20 accumulation [4]. With regard to the social environment, population aging will have various effects on health care, the employment system, the pension insurance system, urban housing and transportation, and old-age service facilities [5]. Furthermore, the regional development imbalance associated with population development factors and socioeconomic characteristics has become a major feature of China's population aging. In view of this, studying the evolution of the spatial differences of China's population aging and its driving factors is conducive to identifying the geographical characteristics of China's population aging and provides a reference for narrowing regional differences, reducing unfavorable socioeconomic impacts and formulating reasonable population development strategies and policies.With the development of industrialization, modernization, and urbanization after the Second World War, developed countries took the lead in completing the modern transformation of population reproduction from high birth and high death rates to low birth and low death rates. The population age structure also changed from young to old. Some scholars have begun to explore the health problems of the elderly and the prevention and treatment of diseases caused by aging from the perspective of biology and medicine [6][7][8]. In the 1970s, geographers interested in aging broadened the understanding of the spatial issues of population aging due to advances in geography, and explored the spatial distribution of the elderly, the dynamic changes in the distribution over time [9][10][11], and the problems urban living spaces create for the elderly [12][13][14]. During this period, several scholars summarized the research on t...
