This research studies the impact of India's declaration of a nuclear explosion on the 18th of May 1974 on the US nuclear non-proliferation policy and its implications for the negotiations of the Iranian nuclear program. And Washington's increasing fears of nuclear proliferation resulting from the Indian nuclear explosion, which led to a major development and shift in the fragile balance of power in South Asia, also increased the risks of nuclear proliferation in regions prone to instability such as the Middle East, which may pose a major threat to security. American nationalism and international stability. This prompted the United States to move immediately to strengthen the Nuclear Non-Proliferation Treaty (NPT) regime, as well as its policy on nuclear exports. This caused a change in Washington’s policy on national nuclear programs and the prospects for nuclear cooperation between the United States and Iran, and made the nuclear agreement with Iran a sensitive and thorny issue. This is due to the difficulty of demanding more stringent control mechanisms on the Shah and elsewhere in the world, after the Indian nuclear explosion showed how any country can easily obtain nuclear weapons technology if necessary. The US nuclear policy toward Iran began to reconcile two opposing purposes: satisfying the Shah’s nuclear desires, and thus maintaining good relations with Tehran, on the one hand; And standing as a guarantor of non-proliferation at the global level, on the other hand.