The paper aims to investigate the influencing factors that drive the temporal and spatial differences of CO 2 emissions for the transportation sector in China. For this purpose, this study adopts a Logistic Mean Division Index (LMDI) model to explore the driving forces of the changes for the transport sector’s CO 2 emissions from a temporal perspective during 2000–2017 and identifies the key factors of differences in the transport sector’s CO 2 emissions of China’s 15 cities in four key years (i.e., 2000, 2005, 2010, and 2017) using a multi-regional spatial decomposition model (M-R). Based on the empirical results, it was found that the main forces for affecting CO 2 emissions of the transport sector are not the same as those from temporal and spatial perspectives. Temporal decomposition results show that the income effect is the dominant factor inducing the increase of CO 2 emissions in the transport sector, while the transportation intensity effect is the main factor for curbing the CO 2 emissions. Spatial decomposition results demonstrate that income effect, energy intensity effect, transportation intensity effect, and transportation structure effect are important factors which result in enlarging the differences in city-level CO 2 emissions. In addition, the less-developed cities and lower energy efficiency cities have greater potential to reduce CO 2 emissions of the transport sector. Understanding the feature of CO 2 emissions and the influencing factors of cities is critical for formulating city-level mitigation strategies of the transport sector in China. Overall, it is expected that the level of economic development is the main factor leading to the differences in CO 2 emissions from a spatial-temporal perspective .