Creditors, such as banks, often use disclosed environmental information to assess a company' s environmental risk and ensure the safety of debt funds. Consequently, carbon disclosures have become an important consideration for creditors when making investments. This study explores the relationship between carbon disclosure and debt financing costs using data on listed companies from 2008 to 2019. The results show that carbon disclosure can reduce the debt financing costs of enterprises, and that this influence is more significant for private companies than for state-owned enterprises. Instrumental variables and Propensity Score Matching (PSM) were used to evaluate the robustness of negative relationships. Furthermore, carbon disclosure has a more significant impact on debt costs with less environmental supervision pressure, weak residents' environmental awareness, and weak product market competition. These findings provide guidance for companies' carbon information disclosure and support the establishment of official carbon disclosure standards.