Based on panel data from 2001 to 2019, the Tapio model was applied to measure the decoupling effect of carbon emissions and economic growth in Jiangsu and Zhejiang regions, focusing on analyzing the characteristics of their municipal spatio-temporal evolution. The results show that the decoupling of carbon emissions and economic growth in Jiangsu and Zhejiang has been realized since 2006. However, the decoupling is weak in most periods. The period-by-period decoupling effect of cities varies distinctly, for example, the decoupling ratio of Hangzhou in the study period is nearly 90%, while that of Xuzhou, Lianyungang, Suqian, Wenzhou and Quzhou is less than 60%, and strong decoupling is dominant after 2013. The time-period decoupling effect of cities shows an evolution of ‘substantial improvement-slight deterioration-basically stable’, mainly due to the deterioration of decoupling effect of Zhoushan, Xuzhou, Huai’an, Yancheng, Zhenjiang, Lianyungang and Suqian. Compared with Jiangsu, Zhejiang has better decoupling effects by time period, such as Hangzhou is in decoupling status, and the last two time periods show strong decoupling. Xuzhou, Huai’an and Zhenjiang are relatively weak, and all of them are degraded to expanding connections during the 13th Five-Year Plan period. On this basis, corresponding countermeasures are proposed.