With the continuous growth of the global population and rapid economic development, the demand for energy is increasing, and the increasing scarcity of energy resources and severity environmental problems have become important factors limiting sustainable economic and social development. Therefore, achieving sustainable energy development has received global attention. The main purpose of this work was to measure the energy efficiency (EE) of different regions based on China’s 2008–2021 panel data using the super-efficient SBM model and to examine the roles of green finance and resource tax policies in promoting energy efficiency using the Tobit model, so as to further improve China’s EE, optimize the energy structure, and improve environmental pollution. We concluded the following: First, the average EE value is about 0.549, and there is high regional heterogeneity, which is high in the east and low in the west. Second, the development of green finance at the national level and in the eastern regions promotes EE and achieves the mutual benefits of economic development and ecological protection, while in the western region, the development of green finance significantly suppresses the EE level and is too low to have a significant effect on EE improvement in the central region. The resource tax policy can significantly improve the EE at the national level and in the eastern region, but on the contrary, it does not have a significant effect on improving the EE in other big regions. Third, the degree of openness to the outside world significantly improves the EE at the national level and in the eastern region. However, in the other two big regions, this effect will not be significant. The effect of the industrialization level on the EE at the national level and in the central and western regions is significantly negative, while in the eastern region, it is negative but not significant. The effect of the energy price level on the EE at the national level and in the central and eastern regions is positive, while it is not significant in the western region. Human capital can improve the regional EE in all regions, and the central region has the highest elasticity coefficient.