美國「一個中國」政策的改變,乃源於美國對兩岸關係的變化。此政策原本是在二次大戰後,美國堅持支持中華民國成為唯一代表中國的聯合國常任理事國。但1971年中華人民共和國進入聯合國取得中國代表權,以及1979年美中(中共)關係正常化後,美國當前的「一個中國」政策在美中《三大公報》與《台灣關係法》影響下丕變。本文以歷史研究法回顧美中關係正常化的歷史及對台灣的影響,以文獻分析法檢視美國官方「一個中國」政策(1972-2011)的文件,並以比較研究法探索此政策各時期的轉變與內涵。總結美國當前「一個中國」政策,在於台海的維持現狀,以維持其自身的國家利益。
The change of United States(U. S.) "One China" policy is originated from the alternative change of the relationship among U.S and the Cross-Strait. After WWII, the policy insisted strongly in supporting Republic of China (R.O.C) to be the only one China representative as permanent member state of United Nation (U.N) security council in 1971, then People's Republic of China (P.R.C) replaced R.O.C in the membership of U.N and in 1979, U. S. developed diplomatic relation with P.R.C (America-Sino Normalization) so that the focus of U.S "One China" Policy had been change by America- Sino "Three Communiqué" and "Taiwan Relations Act". Therefore, with history approach, this article reviews the history of America- Sino Normalization and the policy's impact on Taiwan, and at the same time analyzes the change with library approach, and compare variant-period official documents of U. S. "One China" policy (1972-2011) with comparative approach. As a result, U. S. "One China" policy is provided for keeping Cross-Strait "Status quo" and protecting American national benefits.