This research is based on the companies that participated in the first to third Corporate Governance Evaluation System, and discussed the impact of the implementation of corporate governance evaluation on the cost of debt capital and the impact of evaluation results on the cost of debt capital. This research is based on the analysis of the first to third listing companies in Taiwan Corporate Governance Evaluation System and explores the impact of the implementation of corporate governance evaluation on the cost of debt and the relation between evaluation results and the cost of debt. The empirical results show that: (1) After the implementation of the Corporate Governance Evaluation System, the company's cost of debt is reduced, indicating that the company will actively improve the quality of corporate governance, reduce agency problems, and reduce the probability of information asymmetry after the implementation of the evaluation; (2) The higher the Corporate Governance Evaluation System results, the lower the cost of debt, implying that the Corporate Governance Evaluation System will bring useful information to the creditors.