The reform of mixed ownership has formed a shareholding structure with checks and balances between non state shares and state shares. By studying the relationship between the degree of checks and balances between non state owned equity and state owned equity and the behavior of real earnings management, it is found that the degree of checks and balances of mixed equity significantly inhibits the behavior of real earnings management of state owned enterprises, but when the proportion of state owned equity is smaller than that of non state owned equity, the inhibition effect is weakened. In addition, the degree of checks and balances of mixed shares of financial and foreign equity is stronger than that of private equity. The mechanism test found that the mixed equity balance alleviated the real earnings management behaviors by improving performance and inhibiting the motivation of real earnings management; on the other hand, it reduced the real earnings management behaviors by enhancing internal control. The above conclusions are of certain reference value to the deepening of the mixed ownership reform of state owned enterprises and the supervision of the real earnings management in the mixed reform.