Utilizing a sample of audit events conducted by the Audit Office of the Peoples Republic of China on central enterprises from 2010 to 2018, this study employs a multiperiod differenceindifferences model to examine the impact and mechanisms of national audit on TFP in manufacturing enterprises, as well as the role of inefficient investment pathways. The research reveals that national audit significantly facilitates the improvement of TFP in manufacturing enterprises. This improvement is primarily achieved by alleviating agency problems and restraining excessive managerial consumption. In the process of the national audits impact on TFP in manufacturing enterprises, inefficient investment plays a partial mediating role, indicating that suppressing inefficient investment is a crucial pathway through which national audit promotes the enhancement of TFP. Furthermore, secondary audits positively moderate the impact of national audit on TFP. The promoting effect of national audit is more pronounced in enterprises with high levels of inefficient investment, primarily alleviating the issue of insufficient investment in manufacturing enterprises. The studys findings provide valuable insights for microenterprises to better achieve highquality economic development through audit supervision and suggest a pathway for optimizing audit governance mechanisms.