Abstract: Under the background of speeding up the implementation of green credit policy, carbon information disclosure has become an important factor in creditors' credit decision-making. Taking the listed companies of A-share high-carbon industry in China from 2013 to 2016 as research samples, this paper deeply analyzed the mechanism of carbon information disclosure on debt financing cost. The results show that there is an inverted "U" relationship between carbon information disclosure and debt financing cost, and debt default risk plays the part of mediating effect in the process of carbon information disclosure affecting debt financing cost. That is to say, the initial improvement of carbon information disclosure quality will increase debt default risk, and then lead to the increase of debt financing cost. However, when the quality of carbon information disclosure exceeds a certain threshold, carbon information disclosure can reduce debt default risk and play its role in reducing debt financing cost. Further research finds that the impact of carbon information disclosure on debt financing cost is more significant in low growth enterprises. The reduction of corporate growth level enhances the mediating effect of debt default risk and promotes the impact of carbon information disclosure on debt financing cost. The results provide important reference for Chinese enterprises with different growth levels to effectively use carbon information disclosure to reduce debt financing cost.