There is great difference of independent director system in lawful environment between the United States and China. There is great barrier to give free rein to independent director function and there exists overlapping between independent director system and the function of board of supervisors. The independent director system should not carefully be imported in China but the supervision of director board should be consummated by improving structure of share- hold of listed companies, by reinforcing and consummating the function of director board and by providing small and medium-sized enterprises with necessary control methods.