Abstract:    New digital infrastructure construction is not only a solid base for building China into a strong manufacturing country, a strong network country and a strong digital country, but also a key support for accelerating the transformation and upgrading of China′s industries into digital, intelligent, green and service-oriented industries. In the era of digital economy, the high-quality development of China′s industries is embodied in the digitalization, intellectualization, green and service-oriented development of the industries driven by the new generation of digital technology, and the key is to continuously improve the contribution of green total factor productivity (GTFP) to industrial economic growth, so as to promote the synergistic improvement of economic performance and environmental performance of China′s industries. Therefore, an in-depth analysis of the mechanism and effect of new digital infrastructure construction on the industrial green development efficiency growth has important academic values and practical significance for the construction of a modern industrial system and the deepening of the process of new industrialization.In this paper, industrial economic performance and environmental performance were incorporated into the unified theoretical analysis framework. Based on the perspective of green total factor productivity, this paper explained the theoretical mechanism of new digital infrastructure construction affecting industrial technology efficiency, industrial technology progress and industrial green development efficiency growth through the factor allocation effect, industrial optimization effect, knowledge spillover effect and technology impact effect. Based on the panel data of 48 cities in the Beijing-Tianjin-Hebei, Yangtze River Delta and Pearl River Delta urban agglomerates from 2011 to 2019, this paper used the panel regression model, panel threshold model and spatial Dubin model to empirically investigate the internal action mechanism and spatial influence mechanism of new digital infrastructure construction on China′s industrial green development efficiency from the dual dimensions of internal logic and spatial correlation. The above research is expected to provide valuable reference for accelerating the development of digital, intelligent and green industries and comprehensively promoting the deep integration of digital economy and real economy.The research results of this paper are as follows: new digital infrastructure construction in the three urban agglomerations has significantly promoted the growth of industrial green development efficiency and the improvement of industrial technology efficiency, but inhibited industrial technology progress. The mechanism of industrial technology efficiency improvement has become the core path of new digital infrastructure construction to drive the growth of industrial green development efficiency. New digital infrastructure construction has a significant nonlinear marginal return increasing effect on the industrial green development efficiency growth through different levels of Internet penetration. From the perspective of spatial correlation, the construction of new digital infrastructure still shows significant industrial green development efficiency growth effect, technology efficiency improvement effect and technology progress inhibition effect, but its effect direction and influence intensity will show obvious spatial heterogeneity due to geographical proximity and economic proximity factors.Based on the above research conclusions, this paper put forward the following countermeasures and suggestions: firstly, the top-level design and policy support for new digital infrastructure construction should be strengthened, and the optimal allocation of innovation resources across regions, regional collaborative innovation and open innovation should be promoted, so as to fully release the function of technology progress as the main engine for green and high-quality industrial development. Secondly, based on the deep integration of informatization and industrialization, we should strengthen the key supporting role of new digital infrastructure construction in the collaborative transformation of industrial digitalization and greening, so as to effectively exert the enhancement effect of industrial green development efficiency. Thirdly, new digital infrastructure should be laid out according to local conditions to enhance its compatibility with the industrial spatial layout of urban agglomeration, fully release the technology knowledge spillover effect of new digital infrastructure construction, and drive the improvement of the industrial green development efficiency in urban agglomerations.

Key words: new digital infrastructure construction, industrial green development efficiency, integrated development of industrialization and informatization