Key core technology innovation is a vital source of new quality productive forces. Using the sample of listed companies in the strategic emerging industries from 2010 to 2022, this paper examined the effect of key core technology innovation on firms′ new quality productive forces. The study found that focal firms′ key core technology innovation has significant positive spillovers, and enhances peer firms′ new quality productive forces. The mechanism analysis further revealed that the focal firms′ key core technology innovation promotes the peer firms′ new quality productive forces by stimulating derivative technology innovation. Technological proximity and social proximity play negative moderating roles in the relationship between focal firms′ key core technology innovation and peer firms′ new quality productive forces, while geographical proximity is not significant. This research has uncovered the "black box" of the positive spillover effect of key core technology innovation on enterprises′ new quality productive forces and its mechanisms, and it will offer useful guidance for identifying effective pathways to cultivate new quality productive forces and sustain high-quality economic development.