Starting from the behavior characteristics of major shareholders and based on the information asymmetry theory, this paper studies the relationship between major shareholders" reduction of shares and corporate goodwill impairment by taking A-share listed companies from 2014 to 2018 as samples. The results show that there is a significant positive correlation between the reduction of shares by major shareholders and the impairment of corporate goodwill. The more the reduction of shares by major shareholders, the more likely the impairment of corporate goodwill will occur. Considering the timeliness of information transmission, further research shows that after distinguishing the timing of major shareholders" share reduction, the possibility of corporate goodwill impairment caused by major shareholders" share reduction in the first half of the year is higher than that in the second half of the year, that is, the closer to the balance sheet date, the lower the correlation between major shareholders" share reduction and corporate goodwill impairment. Based on this, this paper puts forward some suggestions, such as standardizing the behavior of major shareholders" reduction, establishing and perfecting the internal equity balance mechanism.