基于企业债务种类和赫芬达尔指数，构建2007～2022年中国上市A股非金融企业债务类型集中度指标，考察其对全要素生产率的影响及其机制。研究发现，债务类型结构的集中显著抑制全要素生产率。机制分析表明，高度债务集中增加企业债务融资成本和融资约束；同时对应企业的债务纠纷发生概率和债务违约风险上升，损害内部治理。异质性分析指出，多元债务类型结构弥补了较差商业信用环境和更严重债务软约束引致的负债治理失效，以及债权人保护和高管金融背景有助于多元债务结构发挥作用。经济后果检验显示，多元债务结构的生产率促进作用利于企业价值提升，增强了“债务异质性”假说的现实解释力。

Based on corporate debt categories and the Herfindahl index, this paper constructs a debt-type concentration indicator for Chinese A-share non-financial listed firms over 2007 to 2022, and investigates its impact on total factor productivity as well as the underlying mechanisms. The result shows that high debt structure concentration significantly restrains the improvement of corporate total factor productivity. Mechanism research indicates that a diversified debt structure serves both financing and governance functions. On the one hand, high debt concentration increases corporate debt financing costs and financing constraints. On the other hand, it is associated with a higher likelihood of debt disputes and default risks, thereby lowering governance quality. Heterogeneity analyses indicate that a diversified debt structure mitigates governance failure stemming from weak trade credit environments and severe debt constraints. Moreover, macro-level creditor protection and firm-level executives’ financial backgrounds enhance the effectiveness of a diversified debt structure. Consequence tests demonstrate that the productivity-enhancing effects of heterogeneous debt structures improve both short-term and long-term corporate performance and growth potential, thereby reinforcing the practical explanatory power of the “debt heterogeneity” hypothesis.