中文摘要：

研究基于异质性理论考察关税减免的贸易二元边际扩张效应，通过GTAP软件分析中国内地与香港双边贸易CEPA协议的远期效应，结果发现两地市场充分自由化后CEPA发挥了同盟区的贸易创造效应，内地对港贸易的二元边际保持明显的增长收益，其中外延边际更为显著。同时发现低替代弹性产品够获得自由化的贸易收益，这显示我国大陆企业具有充分的差异化（多样性）国际竞争优势。研究表明，市场自由化的国际区域性同盟可成为维持和发挥我国出口贸易双重“大国优势”的新来源。

英文摘要：

Based on the heterogeneity theory, this paper analyzes the growth effect of trade margins from tariff relief. We use GTAP software to estimate the effect of CEPA agreement on Mainland and Hong Kong bilateral trade, and find markets liberalization has trade creation effect. Mainland can export to Hong Kong with a significant growth for both intensive and extensive margin. The study also finds that the trade products with lower elasticity of substitution can benefit more from trade liberalization, which indicates that China＇s enterprises have fully differ- entiated competitive advantage. The results show that international alliance through market liberalization can become a new source of trade advantage to help China maintain sustainable trade growth.