党的十九届五中全会明确提出要加快构建“双循环”新发展格局，在这一背景下，关税政策也需围绕扩大开放、促进循环、同时兼顾经济安全的原则调整完善。本文基于国际形势新变化和国内改革发展新要求，从现状分析、理论分析和政策影响三个层面深入探讨了新发展格局下我国关税政策的优化设计。首先，本文基于我国关税制度改革成果，搭建了产品-国家层面的关税数据库，从名义关税水平、实际征收率、有效保护率、以及关税制度的国际比较等多个角度对我国现行关税保护水平进行了系统测算，并指出我国现行关税在统计框架、结构设计和对重点技术行业保护效果上的不足。其次，本文构建了全球价值链下的最优关税理论分析框架，在综合考虑投入产出关联、生产资料间替代弹性差异、重点技术行业规模效益特征的基础上，对关税制度的最优安排进行了一般均衡分析。结果表明：不同部门的最优关税水平存在显著差异；对于行业利润率较高、具有显著规模效益特征的重点技术行业提高关税保护，将会显著促进其边际成本下降和利润提升，带来整体福利的改进；而对纺织服装鞋帽等劳动密集型行业的过度保护则会导致资源的错配并带来整体福利水平的下降。最后，本文采用结构估计和经验分析两种方法对关税减让的政策效果予以评估。一方面，我们基于结构模型对RCEP框架下的关税减让在推动区域内贸易增长、中日韩供应链一体化和我国福利水平提升上的积极作用进行了量化评估和机制分析，并进一步验证了对重点技术行业予以产业扶持、中欧自贸合作等政策调整对我国经济发展的积极影响；另一方面，我们基于2017-2019年的消费品降税政策，对消费品关税减让的价格效应和福利影响进行了经验分析，从价格传导、进口种类增加、竞争促进三个渠道验证了消费品关税减让对降低居民消费支出成本、提升居民福利水平的积极影响，为进一步扩大开放提供实证支撑。基于本文的研究结果，我们从关税统计框架优化、关税结构优化、关税减让方式选择、关税政策与产业政策配套机制等方面提出了政策建议。
The Fifth Plenum of the 19th Central Committee of the Communist Party of China emphasized the need to accelerate the establishment of a new development paradigm. The new paradigm highlights the leading role of the domestic economic cycle, with the international economic cycle as its extension and supplement. In this context, tariff policies are expected to be optimized to better serve to expand opening-up, promote circulation and maintain economic security. This paper focuses on the optimal design of tariff policy in the context of the new development paradigm of China, and the analysis consists of three parts: the descriptive facts of the current status, the theoretical framework and the policy evaluation.Firstly, this paper systematically evaluates the protection level of tariff in China based on the tariff database constructed at HS8 product-country level. We calculate the level of the nominal tariffs, the actual levy rates, and the effective protection rates, and compare the bilateral tariffs between China and its trade partners. The results confirm the achievements of China’s tariff reform since 1990s, but also reveal several deficiencies of China’s current tariff system, including limitations of statistical framework, inappropriate tariff design and insufficient protections for high-tech industries.Secondly, this paper constructs a multi-country multi-sector structure model allowing for the existence of the global value chain. The model embodies the input-output linkages, the elastic substitution among materials and economies of scale into a general framework, under which the optimal tariffs are derived and estimated. The results indicate heterogeneous optimal tariffs across different sectors. In particular, for a high-tech industry characterized with high profit margins and significant economies of scale, a higher tariff would significantly decrease its marginal costs, facilitating the profit shifting towards domestic suppliers and benefiting the whole economy. On the contrary, over-protections for the labor-intensive industries, such as textile and clothing, would lead to the misallocation of resources and decrease the aggregate welfare level.Finally, this paper evaluates the welfare effects of tariff reduction in two ways. On one hand, we quantitatively evaluate the trade and welfare effects of tariff reduction under the RCEP framework. Based on the structure model estimation, we validate the positive role played by the RCEP in promoting intra-bloc trade and China-Japan-Korea supply chain integration, and in increasing China’s welfare. We also verify the positive impacts of policies including subsidies for high-tech industries and China-EU free trade agreement on China’s development. On the other hand, we examine the price and welfare effects of consumer goods tariff reductions during 2017-2019. The results indicate that tariff reductions on consumer goods have caused large declines in duty-inclusive prices and thus cost reductions to importers, which encourages more imports for targeted products, in both quantity and variety. We also find a significant impact of tariff reductions on lowering domestic retail prices through pro-competitive effects. Therefore, the consumer goods tariff reductions since 2017 have significantly improved the welfare of residents by providing a wider range of commodities with lower prices, which provides empirical support for further opening-up.Implied by the findings of this paper, we give policy suggestions from four aspects: the improvement of tariff statistics framework, the optimization of tariff structure, the design of tariff reductions under the regional trade cooperation background, and the coordination between tariff policies and industrial policies.
