Abstract: Different types of environmental regulations cause different changes in the allocation of market resources, which in turn have different effects on total factor energy efficiency. Based on provincial panel data from 2003 to 2018, in this paper, environmental regulations were divided into formal and informal types, a comprehensive index evaluation system was built, the combination of SBM and Meta-frontier model was used to measure total factor energy efficiency considering regional production technology differences, and the panel threshold and the intermediary effect model were used to study the promotion of environmental regulations from both direct and indirect dimensions. Results show that: formal environmental regulations have a positive impact on the improvement of total-factor energy efficiency of China, but the effect will weaken when it exceeds a reasonable threshold; the impact of informal environmental regulations on total-factor energy efficiency is a “U-shaped” trend that first decreases and then increases. Formal and informal environmental regulations can indirectly promote the improvement of total factor energy efficiency by influencing technological innovation and foreign direct investment, and informal environmental regulations have a stronger promoting effect. The industrial structure upgrade has a masking effect in the process of different types of environmental regulations affecting energy efficiency, and the masking effect of informal environmental regulations is greater. Therefore, environmental regulatory tools should be further optimized, and scientific environmental regulatory policies should be used to promote the improvement of corporate innovation capabilities and the increase of high-quality foreign investment, thereby increasing total factor energy efficiency.