By manually sorting out the incremental information of investment items in the audit report from 2013 to 2015, this paper studies the relationship between the incremental information of investment items in the audit opinion and the company’s investment efficiency. The empirical results show that the investment information audit opinion has a positive effect on alleviating over investment, but also has a negative effect on aggravating under investment; the internal governance environment has a regulatory effect. Further test shows that promoting shareholders to strengthen internal supervision is an important way for investment information audit opinion to play its role. The results show that the incremental information related to investment matters in audit opinion has an additional value.