本科论文AbstractThe core of financial management, on the one hand, capital structure affects the financing cost and market value of enterprises, on the other hand, it also affects the governance structure of enterprises. A good capital structure can give full play to the capital cost and market competitiveness of enterprises. A company's capital structure is composed of its liabilities and equity. Liabilities are not only costly but also need to be returned. Equity has a good stability, but its disadvantage is that it is difficult to avoid taxes and it is likely to dilute equity. This paper focuses on whether there can be an optimal capital structure in a continuously changing capital structure. After learning from the theories of capital structure in China and the west, this paper explores the capital structure of Yunda freight, and basically uses tables and report data to clarify the optimal capital structure of Yunda freight, This paper analyzes the reasons why Yunda freight has gradually developed since its listing, and then analyzes the external and internal factors that affect Yunda freight to the optimal capital structure, and points out some good development measures to enable the company to reach the optimal capital structure, to provide assistance for the company's good development and correct operation, and to maximize the company's value. Focus on the analysis of the relationship between capital structure and financial risk of Yunda freight, understand the impact of Yunda freight on financial risk, and put forward the trend of optimizing capital structure of Yunda freight in detail.Key words: Yunda freight; capital structure; financial risk本科论文目 录摘 要........................................