Abstract:Under the background of the integration of the Yangtze River Delta and the construction of the Guangdong-Hong Kong-Macao Greater Bay Area becoming a national strategy, this paper compares and analyzes the conversion level, temporal and spatial evolution laws and regional differences of the two major urban agglomerations, and accelerates the pace and promotion of the replacement of the old drivers of growth for the two major urban agglomerations. The first demonstration effect has important practical significance. The evaluation index system is constructed from the three kinetic energy dimensions of the demand side, the supply side and the structural transformation side, and the combined weighting method is used to calculate the replacement of the old drivers of growth in 36 cities in the two major urban agglomerations from 2012 to 2019. Then we explored the temporal and spatial evolution laws and regional differences of the replacement of the old drivers of growth between the two major urban agglomerations. The study concludes that :①the replacement of the old drivers of growth in the Yangtze River Delta and the Greater Bay Area urban agglomeration shows “N" type and "U" type of fluctuating growth trend respectively, and the characteristics of inadequacy are obvious;②The spatial distribution of the “Southeast High”, the “multi-polar” spatial pattern, and the “hourglass-shaped” spatial hierarchy characteristics, while the replacement of the old drivers of growth in the Greater Bay Area urban agglomeration shows a decreasing spatial distribution from “east to west”, “unipolar” spatial distribution. The spatial pattern of "inverted pyramid" and the characteristics of "inverted pyramid" spatial hierarchy; ③the ductility of the core density curves of the two major urban agglomerations has changed from "right trailing" to "converging" trend, indicating that the two major urban agglomerations regional central cities have transformed from old to new drivers of growth. The phenomenon of central polarization has been improved year by year, and the siphon effect of the central city on the surrounding cities has weakened.