In 2015， the conclusion that the private enterprises have been over-indebted in the research literature is surprising， and it has also caused people to pay attention to the problem of excessive debt of private enterprises. Selecting the financial experience data disclosed by the A-share-listed companies in China from 2009 to 2016 as research samples， studying the government’s continuous strengthening of the supervision of the defaulters after the 18th National Congress of the People’s Republic of China， to alleviate the excessive debt of the private enterprises. The effectiveness of the analysis and further analysis of the agency costs and the level of external marketization strengthen the regulatory role of trustee supervision and ease the excessive debt relationship of private enterprises. The study finds that since the 18th National Congress of the Chinese CommunistParty strengthened supervision of fiduciaries， it has effectively relieved the excessive debt level of private enterprises， and the supervision has been significantly positively related to the over-liberation of private enterprises. The over-indebtedness of private enterprises has been transformed into lower than that of state-owned enterprises； The higher the agency cost， the weaker the effectiveness of the above-mentioned relationship； the higher the marketization level， the higher the implementation of the aforementioned policies； and the lower the level of marketization， the more effective the above policies will be.