In order to study the impact of social responsibility information disclosure and product market competition on the cost of equitycapital, this paper selects the data of Shanghai and Shenzhen A-share listed companies for empirical analysis from 2014 to 2017. The empirical results show that both CSR information disclosure and product market competition can impose have impact on reducing the cost of equity capital. The fierce degree of product market competition affects the relationship between social responsibility information disclosure and equity capital cost, and the more fierce the product market competition is, the more obvious the effect of social responsibility information disclosure to reduce equity capital cost is; the above variable characteristic relationship is more significant in non-state-owned enterprises than state-owned enterprises. According to the research results, the enterprises should pay more attention to the coordinated development of internal and external governance mechanism, improve their own market competition mechanism while constantly strengthening the quality of social responsibility information disclosure, and achieve the purpose of reducing the cost of equity capital; At the same time, the regulatory agencies should strengthen the legislation of social responsibility information disclosure and standardize the development of China's capital market.