【摘要】In this paper,we use different methodologies to study the listed companies in China security market on the relationships between their ownership structure and performance as well as the firm value from 2000 to 2004.We find that the proportion of shares held by institutional investors has positive correlation with the performance and firm value within the same and following period;besides,in state-owned public holding companies,the entry of institution alinvestors increase the market premium remarkably.This paper provides new idea on decreasing of state-owned shares for institutional investors.