The development of new quality productive forces depends not only on technological innovation but is also deeply influenced by the socio-economic systems and national will of a country or a region. How to achieve a faster and better leap in productivity has become a focus of discussion among scholars. However, there is currently no literature that empirically examines whether there is an intrinsic link between the construction of digital infrastructure and innovative industry promotion policies and the development of new quality productive forces, as well as the potential mechanisms and heterogeneity issues. Based on theoretical analysis, this paper uses panel data from 275 prefecture-level cities in China from 2011 to 2021 and employs a multi-period difference-in-difference method to empirically test the impact of the “Broadband China” demonstration city construction and innovative industry cluster pilot policies on the development level of new quality productive forces. The results show that both single and dual pilot policies can significantly enhance the development level of new quality productive forces, and this conclusion remains valid after a series of robustness tests. Compared with single pilot cities, dual pilot cities have a stronger driving effect on the development level of new quality productive forces, and this positive effect is more pronounced in areas that first became innovative industry cluster pilot cities and then “Broadband China” demonstration cities. Promoting economic agglomeration and technological innovation are important mechanisms through which pilot policies drive the development of new quality productive forces. The driving effect of pilot policies on the development level of new quality productive forces is more significant in non-resource-based cities, central cities, large cities, cities with lower constraints on economic growth targets, and cities with a lower degree of economic growth target intensification. Compared with existing research, the marginal contributions of this paper may lie in the following aspects: First, it illustrates the theoretical mechanisms through which “Broadband China” demonstration city construction and innovative industry cluster pilots affect the development level of new quality productive forces, enriches the evaluation index system of new quality productive forces at the city level, and empirically tests the possible synergistic effects between digital infrastructure construction and innovative industry policies, providing a reasonable supplement to existing research results. Second, it introduces two variables (economic agglomeration and technological innovation) to explore the specific paths through which pilot policies empower the development of new quality productive forces. Finally, it examines the heterogeneity of the impact of dual pilot policies on the development of new quality productive forces from aspects such as city differences. The research conclusions not only help to enrich and expand the research on the driving factors of new quality productive forces but also help to fully understand and grasp the synergistic role played by digital infrastructure construction and innovative industry policies in the modern economic system. This paper focuses on the intrinsic logic of how “Broadband China” demonstration city construction and innovative industry cluster pilots jointly empower the development level of new quality productive forces. It helps the government to continuously strengthen policy support for “Broadband China” demonstration city construction and innovative industry cluster pilot work, expand the depth and breadth of policy implementation, fully leverage the synergistic effects of digital infrastructure construction and innovative industry policies, and reasonably arrange the order of policy implementation to help realize the leap in productivity.