Abstract: The long-standing phenomenon of market segmentation in China presents a major obstacle to the construction of a unified national market. Existing research, guided by traditional frameworks analyzing the causes of market segmentation, explores pathways to build a unified national market but largely overlooks the distinctive market integration effects of the digital economy as a new economic form. From the perspective of efficient market and proactive government, this paper employs data from 265 Chinese cities covering the period from 2011 to 2022 to theoretically analyze and empirically test the relationship between the digital economy and the unified national market, along with its underlying mechanisms. The findings reveal that: First, the digital economy significantly reduces the market segmentation index, indicating its effective role in promoting the formation of a unified national market. Second, heterogeneity analysis shows that the promoting effect of digital economy development on market integration is more pronounced in smaller cities, those with lower administrative ranks, and cities located in central or western regions or at provincial boundaries. Third, market and government serve as crucial mediating variables through which the digital economy advances the construction of a unified national market. The digital economy not only optimizes the development and reform of both the market and government sectors but also fosters the organic integration of efficient market with proactive government. Ultimately, it facilitates the formation of a unified national market through three pathways: market forces, government actions, and market-government collaboration.

Key words: digital economy, unified national market, market and government, efficient market, proactive Government