Abstract: The relationship between the resistant power in shareholders and the performances of the listed companies is researched based on empirical study, by means of the analysis of the shareholder structure of the listed companies in Shanghai and Shenzhen stock market A, which has reformed the liquidity of the share structure. We create a scientific formula-- entropy formula, which can measure the degree of the power balance in share structure comprehensively. Results show that equity balance can promote the performances of the competitive companies. Results also reveal that company size has no correlation to company performance, debt rate has negative correlation to company performance, and institutional investors can improve performances of the listed companies.