2008年全球金融危机以来，美元的国际货币核心地位进一步巩固，国际经贸活动中的不平等、货币替代、跨境资本无序流动、支付结算成本高、不透明等长期失衡问题不断加深。央行数字货币作为区块链技术的重要实践应用，对于应对和解决上述问题被寄予厚望。本文充分梳理了跨境支付体系和CBDC的发展现状，围绕国际贸易和国际货币体系提出了源于现实矛盾的研究问题，并从理论和实践两个维度，为解决上述问题展开了前瞻性和创新性的研究工作。在理论层面，考虑CBDC的低成本属性，基于开放经济宏观分析框架创新地引入国际贸中易的汇率价差构建理论模型，得出汇率价差将影响一国宏观经济、货币政策、国际贸易和资本流动，具体为汇率价差会抬高国内融资成本、增大国内货币政策受汇率波动影响以及降低跨境资本流动受实际汇率影响等结论。基于中国2016-2023年以来的汇率价差数据，通过实证模型部分证明了汇率价差对均衡利率、进出口和汇率等存在显著影响，提出了汇率价差可作为政策调控工具的思路。考虑CBDC的便利性、安全性和高效率等属性，构建两国-两阶段OLG经济模型，研究了四种CBDC发行情形的货币均衡条件和经济学意义，并分析了汇率价差对于国际货币均衡的影响，得出未来各国货币竞争将发展成CBDC研发和实践创新的竞争，汇率价差是国际货币体系不均衡、不平等的体现，具有巩固强国货币地位的作用，弱国调降汇率价差有助于提升本国货币国际地位。在实践层面，本文研究提出了基于CBDC的新型跨境支付平台的核心运行机制，包括汇率定价机制、资金流与流动性管理机制等内容。此外，基于某领先跨境B2B电商平台的抽样支付数据估算了新型跨境支付平台汇率定价机制的成本优势，优惠幅度为支付总金额的1?~3‱，相当于节省了传统渠道汇兑成本的1%~10%。综上，本文从多个维度研究证实了CBDC将是未来各国货币竞争的“国之重器”，为各国加快推进CBDC研发和实践创新提供了理论依据，为应用CBDC构建新型跨境支付体系提供了实践探索，为打造更具公平、透明、平衡和可持续的国际贸易新秩序和国际货币体系新格局积累了研究成果，为探索非美货币，尤其是人民币国际化和成为国际货币等课题提供了兼具理论高度和实用性的研究探索。

Since global financial crisis in 2008, the US dollar further consolidated its position as the core of international currency. However, the long-term imbalances in international trade, such as trade inequality, currency substitution, cross-border capital flight, and high cost and non-transparency of payment and settlement, have been deepening. As one of the most important practical applications of blockchain technology, Central Bank Digital Currency is potential for coping with and solving the above problems. Based on reviewing the development status of cross boarder payment system and CBDC, this paper puts forward the research questions from reality around the patterns of international trade and international monetary system. And also conduct a forward-looking and innovative research work to solve the above questions from both theoretical and practical aspects.From the theoretical aspect, due to the low-cost attribute of CBDC, this paper innovatively introduces exchange rate spread of international trade based on open economic macroeconomics theory, and conclude that the exchange rate spread will affect a country‘s macroeconomic, monetary policy, international trade and capital flows, particularly exchange rate spread will raise the domestic financing costs, increase the response of domestic monetary policy affected by exchange rate fluctuations and reduce cross-border capital flows by the actual exchange rate adjustment. Using the data of China‘s exchange rate spread from 2016 to 2023, the empirical model partially proves that the exchange rate spread has significant impacts on the equilibrium interest rate, import and export and exchange rate, and put forward the idea that the exchange rate spread can be used as a policy tool. Due to the convenient, safe and high-efficient attributes of CBDC, this paper builds two country-two stage OLG economic models, studies the four equilibrium conditions of CBDC issuance, demonstrates economic meanings of equilibriums, and concludes that the exchange rate spread has effects on the international monetary system. Therefore, the future currency competitions will become the competitions of CBDC development and practical innovations. And this paper also demonstrates that the exchange rate spread is reflection of the imbalance of international monetary system, which has the role of consolidating the position of strong currency, and meanwhile weak countries can improve the positions of their fiat currencies through the path of setting lower exchange rate spreads of their currencies. From the practical aspect, this paper puts forward several core operation mechanisms of a new cross-border payment platform based on CBDC, including the exchange rate pricing mechanism, capital flow design and liquidity management mechanism, and etc. In addition, based on the sample data of payment of a leading cross-border B2B e-commerce platform, the cost advantage of the exchange rate pricing mechanism is estimated. The discount margin is about 1?~3‱ of the total amount of each payment, which is equivalent to saving 1%~10% of the exchange cost in traditional scenario.In conclusion, this paper confirms that CBDC will be the core of the future of currency competition from multiple dimensions. The research provides theoretical supports that it is necessary to accelerate the CBDC development and practical innovation, demonstrates practical explorations of building a new cross-border payment system using CBDC, accumulates research experiences of creating a more fair, transparent, balanced and sustainable order and pattern of international trade and international monetary system, and explores the research of no-US dollar internationalization, especially RMB internationalization and becoming international currency from both theoretical and practical aspects.