Abstract: Based on the propensity score matching method, this paper explored the impact of research and development subsidies, tax incentives, and their mix on corporate research and development investment from the perspective of financing constraints using the data of Chinese listed companies from 2008 to 2019. It removed confounding factors to make the research results more accurate. The results show that there is a significant difference between the results of removing confounding factors and not removing confounding factors, indicating that the presence of confounding factors would lead to biased results. Under the condition of removing confounding factors, the research and development subsidies or tax incentives have a promoting effect on corporate research and development investment without financing constraints but it is difficult for research and development subsidies or tax incentives to have the original promoting effect on corporate research and development investment when there are financing constraints. However, regardless of whether the corporate is faced with financing constraints, the policy mix of research and development subsidies and tax Unmarked can significantly promote corporate research and development investment. Therefore, the policy mix has a more significant and stable impact on corporate research and development investment than a single policy. This paper contributes to enriching the theoretical research in this field, and providing important reference significance for the formulation of relevant policy mixes in China.

Key words: research and development subsidies, tax incentives, policy mix, financing constraints, research and development investment, confounding factors

摘要： 利用2008~2019年中国上市公司数据，借助倾向得分匹配模型，通过研究设计剔除混杂因素，从融资约束视角探讨研发补贴、税收优惠及其组合对企业研发投入的影响。研究显示，剔除混杂因素与不剔除混杂因素的结果之间存在显著差异，表明混杂因素的存在会导致研究结果有偏。剔除混杂因素后发现：当企业没有面临融资约束时，研发补贴或税收优惠对企业研发投入有显著促进作用；当企业面临融资约束时，研发补贴或税收优惠的创新促进作用难以有效发挥。但是当两种政策组合使用时，无论企业是否面临融资约束，政策组合均能显著促进企业提高研发投入。因此，政策组合相比单项政策对企业研发投入的影响更显著、稳定。研究结论不仅丰富了该领域的理论研究，而且对于中国相关政策组合的制定有重要借鉴意义。

关键词: 研发补贴, 税收优惠, 政策组合, 融资约束, 研发投入, 混杂因素