This study takes the panel data of 278 prefecture-level cities in China from 2011 to 2022 as samples, constructs a super-efficiency SBM model to measure urban energy-environment efficiency, uses the entropy method to synthesize the digital economy composite index, and introduces the green innovation index as a mediating variable. Breaking through the traditional analysis framework in the empirical method: Firstly, through the fixed-effects model and mediating-effect test, it reveals the direct impact of the digital economy on energy-environment efficiency and the transmission path of green innovation. Secondly, it divides the eastern, central, and western regions and low-carbon pilot cities for heterogeneity tests to identify the moderating effect of policy intervention. Thirdly, it strengthens the robustness of the conclusions by replacing the super-efficiency CCR model, shortening the sample period, and performing winsorization. The study finds that the digital economy significantly improves energy-environment efficiency through green technology innovation. These conclusions provide an empirical basis for optimizing the layout of digital infrastructure and improving the regional collaborative emission-reduction mechanism.