由于创新投入的外部性和风险性，企业创新动力较弱，为实现社会发展均衡， 各国政府采取很多税收优惠政策和财政政策激励创新活动。税收优惠政策主要包 括税额减免、降低税率、税基调整。对已有政策所产生激励效果的研究不断出现， 其中降低税率是否能有效激励企业创新存在争议。本研究探究降低税率激励效应 发挥的机制和条件，并尝试探究降低税率对双元创新间的影响。首先从鲜少被关 注的企业追求税盾的角度，考虑企业已有债务税盾水平对激励效应的影响；在此 基础上，探究企业生命周期对激励效应的影响。研究了这两个企业自身特点对激 励效应的影响后，我们考虑除此以外，我国特殊市场法制环境下，企业外部因素 地区法制水平、政府压力会怎样调节降低税率的激励效应。通过研究，希望能理 清降低税率在何种内外部条件下能发挥有效的激励效应，且对双元创新有怎样的 激励效果。 采用双重差分法，以2008年所得税税改革为自然实验样本，探究税率和税 盾利用程度、生命周期、法制化水平、地方政府经济压力四个调节变量对创新投 入和双元创新投入的影响。最终结果显示债务税盾利用程度会减弱降低税率对创 新投入的激励效应，对双元创新无显著影响；企业生命周期的推进会抑制降低税 率对创新投入的激励效应，对探索性创新的抑制作用强于对开发性创新的抑制作 用；法制化水平会加强降低税率对创新投入的激励效应，对探索性创新的促进作 用强于开发性创新的促进作用；地方政府经济压力会抑制降低税率对创新投入的 激励效应，对探索性创新有显著的抑制作用，对开发性创新无影响。在理论层面， 本研究的结论解释了降低税率对创新的激励效果存在争议的原因。在实践层面， 本研究的结论可以为制定降低税率激励政策提供参考，考虑如何减少税收损失、 针对企业特点采取更有效的激励措施。 关键词：税率；双元创新；税盾；生命周期；外部环境 II ABSTRACT Due to the externality and risk of innovation investment, the innovation power of enterprises is weak. In order to achieve a balanced social development, governments adopt many tax incentives and fiscal policies to stimulate innovation activities. The tax incentives mainly include tax reduction, tax reduction, and tax base adjustment. Research on the incentive effects of existing policies has emerged, and it is controversial whether the reduction of tax rates can effectively stimulate enterprise innovation. This study starts from the controversy, explores the mechanisms and conditions for the incentive effect, and attempts to explore the impact of reducing the tax rate on the dual innovation. First of all, from the perspective of the tax shields that few companies are concerned about, consider the impact of the existing debt tax shield level on the incentive effect; on this basis, further consider not only affecting corporate debt levels, but also affecting enterprise innovation decisions. The impact of the life cycle on the incentive effect. After studying the influence of the characteristics of these two enterprises on the incentive effect, we consider that in addition to the special market legal environment in China, the external legal factors of the external factors of the enterprise and the government pressure will adjust the incentive effect of reducing the tax rate. Through research, I hope to clarify the effective incentive effect of reducing the tax rate under what internal and external conditions, and what kind of incentive effect on dual innovation. Using the method of empirical research, the 2008 income tax reform is a natural experimental sample, and each factor is tested as a regulatory variable to observe the four adjustment variables of tax rate and tax shield utilization degree, life cycle, legalization level, and local government economic pressure. The impact on innovation investment and dual innovation investment. The final result shows that the degree of utilization of the debt tax shield will weaken the incentive effect of reducing the tax rate on innovation investment, and has no significant impact on the dual innovation; the promotion of the enterprise life cycle will inhibit the incentive effect of reducing the tax rate on innovation investment and the suppression of exploratory innovation. The effect is stronger than the inhibition of developmental innovation; the level of III legalization will strengthen the incentive effect of reducing the tax rate on innovation investment, the promotion of exploratory innovation is stronger than the promotion of developmental innovation; the local government economic pressure will inhibit the reduction of tax rate The incentive effect of innovation investment has a significant inhibitory effect on exploratory innovation and has no impact on developmental innovation. KEY WORDS：Tax rate, Dual innovation, Tax shield, Life cycle, External environment IV 目 录 摘要 ............................................................................................................................ I ABSTRACT .................................................................................................................. II 目 录 ......................................................................................................................... IV 第1章 绪论 ................................................................................................................ 1 1.1研究背景及现状 .............................................................................................. 1 1.2研究内容和研究创新 ...................................................................................... 2 1.2.1研究内容 ............................................................................................... 2 1.2.2研究创新点 ........................................................................................... 2 1.3关键概念界定 .................................................................................................. 3 1.3.1税率 ....................................................................................................... 3 1.3.2创新与双元创新 ................................................................................... 3 1.3.3企业税盾 ............................................................................................... 4 1.3.4企业生命周期 ....................................................................................... 5 1.4研究方法 .......................................................................................................... 5 1.5研究框架 .......................................................................................................... 6 第2章 基础理论与文献综述 .................................................................................... 9 2.1理论基础 .......................................................................................................... 9 2.1.1税的基本理论 ....................................................................................... 9 2.1.1资本结构理论 ....................................................................................... 9 2.1.2生命周期理论 ..................................................................................... 11 2.2文献综述 ........................................................................................................ 12 2.2.1公司税收与财务决策 ......................................................................... 12 2.2.2创新投入的影响因素 ......................................................................... 14 2.2.3税收激励与创新投入 ......................................................................... 15 2.2.4研究趋势与研究评述 ......................................................................... 17 第3章 研究假设和研究设计 .................................................................................. 19 3.1研究假设 ........................................................................................................ 19 3.1.1降低税率对创新投入和双元创新的激励效果 ................................. 19 3.1.2债务税盾利用程度的调节效应 ......................................................... 20 V 3.1.3企业生命周期的调节效应 ................................................................. 21 3.1.4法制化水平的调节效应 ..................................................................... 22 3.1.5地方政府经济压力的调节效应 .........................