Investigating the regional difference is of enormous practical value in the context of the new normal. Only a few studies, however, explored the regional difference in high-quality development from the perspective of coupling coordination. Based on the panel data set covering China's 30 provinces during 2003-2020, this study explores the spatiotemporal distribution characteristics, regional differences, and obstacle factors of the coupling coordination degree of high-quality development. The results show that: (1) Innovation is the main factor limiting high-quality development. Greenness is the main weak point of the eastern regions; The disadvantages of the central, northeast, and western regions are mainly openness. (2) The coupling coordination degree of high-quality development is low, with a significant spatiotemporal differentiation. The regional difference of coupling coordination degree is reduced, and the main source is the inter-regional difference. (3) The obstacle factors of coupling coordination degree have changed over time. Obstacle factors of the national, eastern, central, and northeast regions are the subsystem of carbon emissions; Obstacle factors of the western regions are distributed in the economy, greenness, coordination, and innovation. Based on the perspective of coupling coordination, this paper proposes policy recommendations for the synergy evolution of China's high-quality development.