Based on the analysis of property right character of the banking industry in China, this paper empirically tests the signal effect of the voluntary audit of internal control on the size of bank loan that the firms have borrowed from 2008 to 2011. The results show that, on the whole, the signals of voluntary internal control audit help the company get more bank loans, but the signaling is affected by the heterogeneity of the banking property rights. Namely, the companies that voluntarily issue the audit report of internal control cannot lend more from the state-owned banks, but can lend more from the private-owned banks. The evidence also shows that Big4 which represent the high-quality signals of the voluntary audit of internal control do not help the companies lend more from the state-owned banks or the private-owned banks. The results show that China’s state-owned banks have insufficient demand for internal control audit, and both state-owned banks and private banks lack the demand for high-quality internal control audit.