Integrating dispersed and closed regional markets and building a unified and open national market system not only generates greater professional division of labor advantages, improves resource allocation efficiency, but also creates broad market space for industrial development. Can this promote the formation of strategic emerging industries and future industries, and promote the development of new quality productivity? This article is based on provincial-level panel data in China from 2010 to 2022. The entropy method is used to construct new quality productivity indicators from three dimensions: technological productivity, green productivity, and digital productivity. Multiple econometric techniques such as the double fixed effects model, two-stage least squares method, and spatial Durbin model are used to analyze the impact of the construction of a unified national market on the development of new quality productivity. The study finds that, overall, the construction of a unified national market can help improve new quality productivity. After endogeneity testing, and other robustness tests such as replacing core explanatory variables, replacing dependent variables, and deleting special samples, it still holds. The mechanism of action test finds that the construction of a unified large market has expanded market demand, promoted basic research, stimulated entrepreneurial spirit, and further promoted the development of new quality productivity. Heterogeneity analysis reveals significant regional and dimensional heterogeneity in the impact of the construction of a unified national market on the development of new quality productivity. At the regional level, compared to the eastern region, the supportive effect of the unified large market on the development of new quality productivity is more significant in the central and western regions. At the dimensional level, the construction of a unified national market can effectively promote the development of technological and digital productivity, but its impact on green productivity has not yet been apparent. The analysis of spatial spillover effects finds that the unified market not only promotes the development of new quality productivity in the local area, but also promotes the development of new quality productivity in other surrounding areas. The characteristics and innovation of the article are mainly reflected in: 1) Research perspective. Based on the background of the construction of a unified national market, this study examines the impact of the construction of a unified national market on the development of new quality productivity, providing a new perspective supplement for related research. 2) In terms of research content. New quality productivity is the innovation and practice of Marxist productivity theory in China. This article demonstrates the necessity and effectiveness of promoting the improvement of new quality productivity through the construction of a unified large market from both theoretical and empirical perspectives, and further tests the spatial spillover effects of the development of new quality productivity, elevating research on the consequences of a unified large market economy to a new level. 3) At the policy level. Based on three aspects: basic research, market demand, and entrepreneurial spirit, this paper deeply analyzes the mechanism of the unified market’s impact on new quality productivity, and analyzes the path to enhance new quality productivity, which has important policy reference value. This study may deepen the understanding of market-oriented development path of new quality productivity.