Environmental sustainability has become a significant goal for policymakers and practitioners since increasing environmental degradation owing to anthropogenic activities. Energy-environment efficiency, linked to a progressive reduction in the environmental impacts that may occur throughout their life cycle to levels that should be below or equal the Earth's estimated carrying capacity, is a crucial point for constructing an environment friendly society while maintaining rapid economic growth. Thus, this study combined a slack-based measure (SBM) with environmental impacts as undesirable outputs with spatial analysis techniques to measure energy-environment efficiency of 21 cities in Guangdong and its changing patterns during the period 2006-2016. What and how socioeconomic factors affecting energy-environment efficiency over time and space was further examined using heterogeneous panel data model. Here are the main findings: during the study period, energy-environment efficiency showed apparent spatiotemporal diversity with high values predominantly concentrated in coastal areas, especially in the center area of the Pearl River Delta. Energy-environment efficiency increased continuously in the western Guangdong and the Pearl River Delta, while it of eastern Guangdong showed a decreasing trend and of northern Guangdong remained stable at a low level. The results of the heterogeneous panel data model revealed that technological progress exerted the greatest positive effects on energy-environment efficiency, followed by population density, economic growth. Conversely, Openness was evaluated as an inhibiting factor. Interestingly, this study found that industrial structure demonstrated significant negative correlations with respect to energy-environment efficiency in the Pearl River Delta while it exerted significant positive influence in the peripheral areas of Guangdong. And foreign trade and energy-environment efficiency had a significant positive correlation in the Pearl River Delta, unlike the negative correlation in the peripheral areas of Guangdong. This study's findings hold a helpful reference for both policymakers and practitioners to coordinate the economy, energy and environment and established environment-friendly society in the fast-developed areas like Guangdong.