数字经济对中国向东盟出口绩效的影响：理论机制与模型分析

The Impact of the Digital Economy on China’s Export Performance to ASEAN: Theoretical Mechanisms and a Model Analysis

摘要: 数字经济正在重塑中国与东盟的贸易联系，但其作用于出口绩效的内在机理尚缺乏统一的理论刻画。本文在垄断竞争与异质性企业框架下构建含质量与贸易成本的局部均衡模型，把数字经济的影响分解为贸易成本、质量升级与匹配–扩展边际三条路径，并推导出口额对数字经济水平的弹性表达式。分析表明：数字经济压低双边冰山贸易成本以提升集约边际，降低质量提供成本以推动质量升级，改善供需匹配、削减固定进入成本以扩大扩展边际；三条路径净效应恒为正，且在各渠道弹性不变时，成本效应与质量效应均随替代弹性上升而增强，替代弹性较大的产品对数字经济更敏感。据此提出以数字基础设施互联、跨境电商与数字贸易规则对接、出口质量与韧性培育为重点的政策方向，并讨论了局部均衡设定的局限。

Abstract: The digital economy is reshaping China-ASEAN trade, yet the mechanisms through which it affects export performance lack a unified theoretical account. Within a monopolistic-competition and firm-heterogeneity framework, this paper builds a partial-equilibrium model with quality and trade costs, decomposing its effect into three channels—trade cost, quality upgrading, and matching-extensive margin—and derives the elasticity of export value with respect to the digital economy. The digital economy raises the intensive margin by lowering iceberg trade costs, drives quality upgrading by reducing the cost of providing quality, and expands the extensive margin by improving matching and cutting fixed entry costs. The net effect is unambiguously positive, and both effects strengthen as the elasticity of substitution rises when the channel elasticities are held constant, implying that products with a higher elasticity of substitution exhibit greater export responsiveness to the digital economy. The paper proposes policy directions centred on digital infrastructure connectivity, alignment of cross‑border e‑commerce and digital trade rules, and the cultivation of export quality and resilience, and notes the limits of the partial‑equilibrium setting.