本研究應用Barten（1993）一般化需求體系（general synthetic demand system，簡稱SYN）及與其嵌套的需求體系分析美中貿易戰前後全球主要吳郭魚供應國（包含臺灣）在美國市場的進口需求結構變化。其結果顯示，由具混合CBS 型態變動的支出項與鹿特丹（Rotterdam）型態固定價格項的需求體系適用於美國吳郭魚冷凍魚片進口需求；美國吳郭魚冷凍全魚進口需求則由以具鹿特丹型態固定支出項與NBR 型態變動價格項混合的模型較為適合。美中貿易戰後，美國吳郭魚冷凍魚片的進口需求結構有顯著的改變，各進口國包含中國、印尼、臺灣及其他國家等自身價格彈性變得更具有彈性，中國進口價格對我進口量的影響減弱，印尼與我國產品之間的替代競爭關係顯著增強，其他國家與我魚片的替代競爭關係減弱。然而美中貿易戰對美國吳郭魚全魚進口需求結構未產生顯著的影響，中國與臺灣冷凍全魚的支出彈性顯著且均小於一，越南及其他國家則顯著大於一。中國冷凍全魚的自身進口價格彈性不具彈性，臺灣則顯著具彈性。泰國與我國的冷凍全魚之間有顯著的替代競爭關係，然而中國進口價格對臺灣進口量的影響則不明顯。

This study applies Barten (1993) general synthetic demand system approach with its nested models to analyze the changes in the import demand structure of Tilapia in US during the US-China trade war. The results show that the model mixed by the CBS type expenditure response and Rotterdam type price response demand system is the best to describe US Tilapia fillets import demand. While the mixed model of Rotterdam type expenditure response and NBR price response is the best model for the US Tilapia Frozen whole fish import demand. US Tilapia fillets import demand structure has been significantly impacted by the US-China trade war. The importing countries, including China, Indonesia, Taiwan, and rest of world, have become more flexible in their price elasticity. The influence of China’s import prices to Taiwan import quantity has become weakened, whereas the substitution between Indonesia and Taiwan becomes stronger. While the US-China trade war has no significant impact on the structure of U.S. Tilapia whole fish import demand. China’s own import price elasticity of frozen whole fish is not elastic, while Taiwan’s is significantly elastic. There is a significant competition relationship between Thailand and Taiwan’s frozen whole fish, but the impact of Chinese import prices on Taiwan import quantity is not significant.