Based on the data of internal control defects and audit fees disclosed by A-share listed companies in China from 2012 to 2016， this paper makes an in-depth study on the impact of internal control defects disclosure on the implementation cost of internal control of enterprise after mandatory internal control audit in China. The study finds that in the first year of enforcement of internal control audit and subsequent years， the disclosure of internal control defects by enterprises leads to an increase in the cost of internal control implementation of enterprises. At the same time， the prior internal control defect disclosure will also increase the cost of internal control implementation in the current period. Further research finds that the severity of internal control defects disclosure is also significantly positively correlated with the implementation cost of internal control. The more serious of the internal control defects disclosed by enterprises， the higher of the implementation cost. However， the rectification of internal control defects taken by enterprises will reduce the implementation cost.