This paper analyzes the impact of business entertainment expenses on corporate performance, and adjustment effect of an "eight-point" guideline on the impaction. Using China's A-share 855 listed companies in 2011-2014 as research samples, this study finds that, business entertainment expenses have an inverted U-shaped relationship with corporate performance, the impaction of business entertainment expenses on corporate performance partly was replaced by internal control; Moderate levels of business entertainment expenses works best. There is a more significant substitution effect between eight regulations and internal control.