As effective policy tools for driving urban smart and green development, the Smart City Pilot and Low-Carbon City Pilot can improve resource allocation and the business environment in pilot cities, thereby synergistically driving the agglomeration of the digital industry towards these dual-pilot cities. Taking the Smart City Pilot and Low-Carbon City Pilot as quasi-natural experiments, using the location entropy of employees to measure the degree of urban digital industry agglomeration, and employing panel data from 298 prefecture-level cities in China from 2006 to 2023 for a multi-period difference-in-differences test, the analysis reveals that China’s digital industry has developed an agglomeration pattern characterized by leadership of the eastern region, simultaneous rise of the central and western regions, belt-like continuous distribution, and multi-center coordination; the dual pilots of Smart City and Low-Carbon City significantly promote digital industry agglomeration in dual-pilot cities, and the policy effect strengthens with the duration of the pilots, with the effect of dual pilots being greater than that of single pilots; the dual pilots can promote digital industry agglomeration through three pathways: promoting digital technological innovation and green technological innovation, and increasing human capital accumulation; the dual pilots significantly promote digital industry agglomeration in cities with higher economic development levels and better environmental foundations, but their impact on cities with lower economic development levels and poorer environmental foundations is not significant. Therefore, it is necessary to deepen “intelligence + green” policy synergy and build a new pattern of gradient development for the digital industry with regionally differentiated strategies.