Abstract: The long-standing regional disparities in environmental supervision have hindered the cultivation and development of a unified national ecological environment market. As a re-supervision mechanism for supervisors, national auditing plays a positive role in serving the construction of ecological civilization. Using the data from prefecture level cities from 2011 to 2022, this study empirically examines the impact of national auditing on environmental regulatory differences between regions. The findings reveal that national audits can narrow environmental regulatory differences between regions. The mechanism analysis shows that national auditing can suppress local protectionism behavior of local governments and promote collaborative cooperation in environmental regulation between regions. Therefore, national auditing can“narrow up”the differences in environmental regulation between regions. The heterogeneity analysis reveals that in cities with high levels of digital economy development and efficient government environmental governance, national auditing is more effective in narrowing environmental regulatory differences between regions. To this end, it is necessary to strengthen the power of national audit re-supervision, leverage the regional coordination and linkage effect of national audit, and help cultivate and develop a unified national ecological environment market.

Key words: government audit, regional disparities in environmental supervision, ecological environmental market