Abstract: ased on panel data from the Yangtze River Delta urban cluster from 2011 to 2021, this study employed a global technology super-efficiency hybrid distance function and a mediation effects model to analyze the impact of new infrastructure construction, particularly in the areas of information, innovation, and integration infrastructure, on the "quality and efficiency" of low-carbon economic development. Additionally, this study explored the mediating role of green technological innovation. The findings were as follows: (1) New infrastructure and information infrastructure had a significantly positive impact on the "quality and efficiency" of low-carbon economic development in the study area. The green technological innovation was found to play a significant mediating role. (2) Innovation infrastructure primarily had a significantly positive impact on the quality level of low-carbon economic development. Innovation infrastructure enhanced the transformation and upgrading of the economic structure and promoted the research and application of green technologies. However, due to the factors of diminishing marginal returns on capital, inefficient resource allocation, and low technological conversion efficiency, the driving force on the efficiency level of low-carbon economic development was limited. (3) Integration infrastructure faced certain challenges including insufficient synchronicity between information technology and integration infrastructure, low maturity and stability of emerging technologies, and difficulties in applying them within the complex open systems. These constraints hindered the driving capacity of integration infrastructure on regional low-carbon economic development. Finally, we provided recommendations including strengthening regional and industry collaboration, improving technological conversion efficiency, optimizing resource allocation mechanisms, and establishing a multidimensional evaluation system.