This research, set against the backdrop of rapid global advancements in green technology innovation and aligned with China’s sustainable development strategy, conducts an in-depth analysis of the spatiotemporal disparities and spatial spillover effect of a low-carbon economy in Chinese provinces. Following empirical analysis and data testing, the study draws the following conclusions: (1) China’s low-carbon economy is subject to significant regional differences. Over time, the development level has improved annually, with the number of provinces above the middle level of low-carbon economy rising from 11 in 2010 to 22 in 2022. However, regional differences persist. The eastern region has shown the most significant progress, while the central area encountered its initial challenges first, and the development of the western area has unfolded in a more segmented manner. (2) In this paper, the low-carbon economy in China shows notable characteristics of spatiotemporal agglomeration, with the number of high–high agglomeration provinces rising from four in 2010 to seven in 2022, an increase of 78% year-on-year. The number of provinces and provinces in the low–low agglomeration mode increased from two in 2010 to six in 2022, a year-on-year increase of 200%. (3) China’s low-carbon economy demonstrates notable spatiotemporal evolution. The development process tends to remain stable during transitions, with a high likelihood of sustaining the current state while gradually advancing, avoiding abrupt changes across levels. (4) Innovations in green technology exert a positive influence on the advancement of the low-carbon economy, with a clear spatial spillover effect. In light of these findings, the research offers targeted recommendations for society, enterprises, and government stakeholders.