Social responsibility fulfillment helps modern enterprises achieve sustainable development. Based on empirical data on China's A-share listed companies in 2013-2016, this paper examines the impact of corporate social responsibility performance on a company's financing costs from the perspective of targeted poverty alleviation. Specifically, we find that enterprises' engagement in poverty alleviation social responsibility helps to reduce the cost of equity capital. The result is robust to using alternative indicators of the cost of equity capital, propensity score matching method, change model and sample removed financial sector. Furthermore, we find that the negative relationship between enterprises' engagement in poverty relief and the cost of equity capital is mainly concentrated in private enterprises and in the central and eastern regions of China. Moreover, the negative relationship mainly exists after China's listed companies were forced to disclose information on poverty alleviation. This paper also finds that institutional investors' shareholding plays a partial mediating role in this reduction effect and that enterprises' poverty alleviation efforts help companies improve their financial performance and firm value. This study enriches the relevant literature on corporate social responsibility and the cost of equity capital and has reference value for corporate sustainable development. It also provides a theoretical basis for corporate poverty alleviation work in developing countries and the economic results of CSR.