Governments around the world have adopted a series of policies and instruments to mitigate climate warming, environmental pollution, and other issues that affect human survival and development. Among them, emission taxes are levied to regulate manufacturers’ emission reductions, and subsidies are used to encourage green innovation. However, so far, little attention has been paid to the mechanism of the impact of joint tax-subsidy policies on green innovation and the design of optimal tax-subsidy policies. To fill this gap, this paper develops a Stackelberg differential game model between a regulator and a polluting oligopoly. In this model, the regulator firstly issues a joint tax-subsidy policy, and then the pollution oligopoly determines the level of green innovation effort in the light of the regulator’s policy. In particular, for the first time, both efficiency-improving and cost-reducing learning by doing in green innovation are considered simultaneously. The results show that the joint tax-subsidy policy can lead to higher social welfare and higher investment levels in green innovation than a single tax or subsidy policy. Moreover, learning-by-doing in green innovation can substitute part of the innovation investment, while improving environmental quality and social welfare, especially under the joint tax-subsidy policy. As a result, a joint tax-subsidy policy needs to be adopted and dynamically adjusted to different implementation contexts.

世界各国政府已经采取了一系列政策和手段来减轻气候变暖，环境污染以及其他影响人类生存和发展的问题。其中，征收排放税以规范制造商的减排量，并通过补贴鼓励绿色创新。但是，到目前为止，关于联合税收补贴政策对绿色创新的影响机制和最优税收补贴政策的设计，人们很少关注。为了填补这一空白，本文建立了监管者与污染性寡头之间的Stackelberg差分博弈模型。在此模型中，监管机构首先发布联合税收补贴政策，然后污染寡头根据监管机构的政策确定绿色创新工作的水平。尤其是，首次同时考虑了通过绿色创新来提高效率和降低成本的学习方式。结果表明，与单一税收或补贴政策相比，联合税收补贴政策可以带来更高的社会福利和更高的绿色创新投资水平。此外，绿色实践中的边干边学可以替代部分创新投资，同时改善环境质量和社会福利，尤其是在联合税收补贴政策下。因此，需要采用联合税收补贴政策，并根据不同的实施环境动态调整税收政策。结果表明，与单一税收或补贴政策相比，联合税收补贴政策可以带来更高的社会福利和更高的绿色创新投资水平。此外，绿色实践中的边干边学可以替代部分创新投资，同时改善环境质量和社会福利，尤其是在联合税收补贴政策下。因此，需要采用联合税收补贴政策，并根据不同的实施环境动态调整税收政策。结果表明，与单一税收或补贴政策相比，联合税收补贴政策可以带来更高的社会福利和更高的绿色创新投资水平。此外，绿色实践中的边干边学可以替代部分创新投资，同时改善环境质量和社会福利，尤其是在联合税收补贴政策下。因此，需要采用联合税收补贴政策，并根据不同的实施环境动态调整税收政策。