In China, power consumption in the steel industry accounts for about 9% of the whole society's power consumption. There is a big gap between the power efficiency of China's steel industry and the world's advanced level, and the power efficiency varies greatly in all regions of China. By using the three-stage data envelope analysis model, this study analyzes the influence of external factors (including environmental regulation, industrial structure, and trade openness) on the power efficiency of the steel industry in 28 provinces of China. Overall, the power efficiency of the steel industry in the eastern, central, and western China present the high, middle, and low power efficiency, respectively. The results reveal that improving trade openness and optimizing industrial structure are conducive to improving the power efficiency, while improving the intensity of environmental regulation can cause the excessive substitution of power sources for other energy resources so as to decrease the power efficiency. Moreover, power efficiency in the eastern and western China are more affected by the external factors than it in the central China. The research conclusions are favorable to introduce different measures for various regions so as to reduce the gap in power efficiency of the steel industry. (C) 2019 Elsevier Ltd. All rights reserved.