The quality of internal control is significantly related to the amount of commercial credit financing according to the previous concerning literature.These cannot show the contribution of internal control to the commercial credit.This paper proposes that the real implemented efficiency of internal control be to enhance the quality of credit assets and credit financing.The empirical results of Chinese listed companies from 2012—2014 show that firms with higher efficiency of internal control are more likely to have a higher quality of credit assets and credit financing.Moreover，the results also show that efficiency of internal control has no significant correlation with the net amount of commercial credit.The role of internal control can not only substitute for power market partly，but also supplement its deficiency.This paper provides more evidence that implementation of internal control system can improve the enterprise credit management quality，and suggests that the overall implementation of internal control system improve the turnover efficiency of social capital.