Abstract: In a context of modern capital market, the first issue that must be solved in a firm's equity financing is to determine the systematic risk of equity capital compared with the entire market, and further to obtain the reasonable level of rate of return to equity investors. This paper used a rolling method to measure theβ coefficients of equity capitals in 30 listed A-share steel making companies in China. The results by the rolling method are more stable compared with the ones by traditional measurement methods, which means the results are more relevant to the financial decision-making for listed A-share companies.