本文分析1979年迄今，美國與伊朗針對伊朗核計畫爭議之競爭與合作，兩國於1979年伊朗爆發革命後，雙邊關係長期不睦，在美國持續為中東最大區域外強權之背景下，伊朗歷屆政府對於美國在中東體系之壓力，採取不同應對措施。其中，哈塔米政府為防範小布希政府可能的軍事行動，曾短暫採取配合態度；內賈德政府時期，小布希及歐巴馬政府陷入伊拉克戰後紛亂，伊朗改採強硬發展核計畫之政策，促使安理會聯手處理伊朗核問題，並通過制裁伊朗決議，所幸羅哈尼政府採取務實及和解政策，與六方達成核子協議，以抑制核子活動換取聯合國解除部分制裁，美國與伊朗關係稍有和緩；俟川普政府退出協議，兩國關係旋即惡化，直接導致核問題升溫；儘管美拜登政府與伊朗萊希政府均有意重返協議，然兩國在中東政治及安全領域之競爭不會歇止，雙邊關係仍將緊繃，對伊朗核問題發展投下重要變數。

This article offers an analysis of the competition and cooperation between Iran and U.S. in terms of nuclear dispute since 1979. The Islamic Revolution of 1979 put the U.S.-Iran relations into an adversarial situation. Iran’s successive governments responded to pressure from the U.S. dominance in the Middle East system with different policies on background that U.S. remains the most powerful country from outside the Middle East. Among Iran’s previous governments, the Khatami government temporarily cooperated with U.S. in a short period of time to prevent the preemptive strike by the Bush administration. During the tenure of Ahmadinejad government, the Bush and Obama administrations had been mired in Iraq post war chaos. Iran changed to a hardline policy of developing a nuclear program which brought the United Nations Security Council to passing resolutions of sanctions against Iran. Fortunately, the Rouhani government adopted a pragmatic and reconcile policy which helps to the singing of the Joint Comprehensive Plan of Action. Under the JCPOA, Iran restrained its nuclear program in exchange of some sanctions relief and thus improved its relations with the U.S. Nevertheless, the Trump administration unilaterally withdrew from the JCPOA and re-imposed economic sanctions on Iran, which deteriorated the bilateral relations and aggravated the nuclear dispute. Even though both the Biden administration and the Raisi government are willing to return to the JCPOA, the competition in the areas of politics and security in the Middle East will not stop. The tense relations between the U.S. and Iran will cast an important variable to the development of the Iran nuclear dispute.