The strategic cycle of "two fifteen years" of China's modernization in the new era is exactly the period of rapid population aging, and the imbalance between the rapid aging of the population age structure and the development of the economy and society will become increasingly serious. This paper uses the data of the fourth, fifth and sixth censuses of Guangdong Province, the sample survey data of 1% population in Guangdong Province in 2015, the data of Hong Kong Statistical Yearbook and Macao Statistical Yearbook. Spatial autocorrelation analysis, Cobb Douglas production function and spatial regression methods were used in this study, the spatio-temporal characteristics and economic effects of population aging in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2015 were studied. The results of our study show that: (1) The aging process of population in the Greater Bay Area is slower than that of Guangdong and even slower than that of the whole country, but it transformed into the senile type I in 2015. (2) The aging coefficient of the study area shows a dynamic evolution feature. The spatial pattern of "C" type started from Hong Kong and Jiangmen of Guangdong and spread northward through the northwest. High income cities spread northward from Macao and Hong Kong, and finally formed a center-periphery distribution pattern. (3) The aging population in the Greater Bay Area has a negative impact on economic growth. The aging population increased by 1%, and the per capita GDP decreased by 3%. Per capita fixed capital investment and per capita human capital investment had positive effect on economic growth, and the positive effect of per capita human capital investment was greater than that of per capita fixed capital investment. In view of this, Guangdong, Hong Kong and Macao should establish a collaborative governance model and build a cross-border pension cooperation mechanism. It is essential to promote industrial restructuring and encourage technological innovation, assess the impact of population aging on economic growth at different stages, and handle the relationship between population aging and economy.