New quality productive forces is a concrete manifestation of advanced productivity, which is driven by technological innovation, and improving the level of intellectual property protection is an important way to ensure the development of new quality productive forces in enterprises. Using the intellectual property demonstration cities gradually established nationwide in 2012 as a quasi natural experiment, the impact of strengthening intellectual property protection on the new quality productive forces of listed companies was evaluated. Research has found that intellectual property demonstration city policies can significantly promote the development of new quality productive forces in enterprises, and this conclusion still holds true after multiple robustness tests. The establishment of intellectual property demonstration cities can optimize regional digital ecology, promote digital transformation of enterprises, and have a positive impact on the development of new quality productive forces of enterprises. The establishment of intellectual property demonstration cities has spillover effects on surrounding cities with high levels of intellectual property protection, but has a siphon effect on surrounding cities with low levels of intellectual property protection. The promotion effect of the construction of intellectual property demonstration cities on the development of new quality productive forces in technology intensive enterprises, growth stage enterprises, non-state-owned enterprises, manufacturing enterprises, and enterprises with rapid technological changes is more significant. The research conclusion reveals the laws and mechanisms of how the construction of intellectual property demonstration cities can improve the new quality productive forces of enterprises, which can provide certain references and policy inspirations for the formulation and implementation of policies related to intellectual property protection and the improvement of new quality productive forces of enterprises.