Abstract: Fostering the rapid development of new quality productive forces is not only a developmental imperative but also a reform imperative. This paper empirically analyzes the impact and mechanism of comprehensive deepening of reforms on the development of new quality productive forces based on panel data from 285 prefecture-level cities in China from 2012 to 2022. The study finds that comprehensive deepening of reforms significantly promotes the development of new productive forces, with a stronger enabling effect on the infiltration dimension of new productive forces. Mechanism analysis reveals that comprehensive deepening of reforms indirectly enhances the development level of new quality productive forces through the resource allocation effect, which optimizes the allocation of production factors and industrial resources. Moreover, a healthy and favorable business environment plays a significant positive moderating role in promoting the development of new quality productive forces. Heterogeneity analysis further uncovers that the promotional effect of comprehensive deepening of reforms on new quality productive forces exhibits heterogeneity in terms of time, geographical location, education level, and new quality productive forces level. The boosting effect of comprehensive deepening of reforms is more pronounced in samples from the acceleration period of reforms, eastern regions, areas along the Hu Line, southeastern regions, and those with high education and high new quality productive forces levels. This study provides theoretical and empirical evidence to understand the role of comprehensive deepening of reforms in the development process of new quality productive forces, and it offers profound insights and practical implications for promoting the massive emergence of new quality productive forces in China.