How Does Industrial Restructuring Improve Regional Energy Efficiency? An Empirical Study Based on Two Dimensions of Magnitude and Quality

China's economic development under the new normal will face increasingly serious energy and environmental constraints, but there is little space for energy savings and emission reduction by further optimization of energy structure, and the advancement of strategic adjustment to industrial structure is the most important and most realistic way to improve energy efficiency. This paper analyzes the evolution characteristics of the adjustment to industrial structure and changes in energy efficiency and their correlation from two perspectives of adjustment width and adjustment quality, and empirically tests the spatial spill-over effect of the adjustment to industrial structure on energy efficiency. It arrives at the conclusions as follows:firstly, with the adjustment to industrial structure, Chinese urban energy efficiency shows an M-type trend, and there are significant spatial spillover effects and interactive coupling relationship between industrial restructuring and energy efficiency; secondly, the improvement of the quality of industrial restructuring has significantly promotion and spatial spillover effects on energy efficiency, but the expansion of the magnitude of industrial restructuring has a significantly inhibitory effect on energy efficiency; thirdly, for regions, the improvement of energy efficiency in eastern and western regions should give priority to the improvement of the quality of the adjustment to industrial structure, to avoid production efficiency losses resulting from simply suppressing the second industry and developing the third industry or simple industrial & labor transfers, and central regions should make full use of the spatial spill-over effect of the quality of the adjustment to industrial structure on the improvement of energy efficiency to perfect energy efficiency of neighboring areas, while they continues to expand the magnitude of the adjustment to industrial structure through undertaking industrial transfers.