"优化资本结构" can be translated into English as "optimize the capital structure" or "improve the capital structure".
Both expressions are commonly used in financial and business contexts to convey the idea of refining or enhancing the composition of a company's capital, which typically includes a mix of debt and equity.
"Optimize the capital structure" emphasizes the goal of achieving the most efficient or effective mix of capital sources.
"Improve the capital structure" focuses on making positive changes or enhancements to the existing capital structure.