Tax avoidance has been a hot topic of theoretical exploration. While there are many researches on the economic consequences of tax avoidance, few focus on the influencing factors. As a complete set of tools of risk management and control, whether internal control restrain the risk of major shareholders tunneling caused by tax avoidance has yet to be tested empirically.Based on this,the paper tests empirically how internal control affects the risk of major shareholders tunneling caused by tax avoidance.The results show that high quality internal control can effectively control the risk of major shareholders tunneling caused by tax avoidance.Further testing shows that the risk control effect of internal control lies in the private enterprises with strong demand for internal control and in the samples with poor quality of accounting information disclosure.By distinguishing the five elements of internal control, we find that risk assessment has a more direct impact on risk management and control. Generally, internal control is an effective institutional tool of risk control.