1949年國民黨政府在內戰中全面潰敗並撤至臺灣，憑藉著美國在經濟以及軍事上的援助，使得中華民國方得以在風雨飄搖的國際局勢中生存。因此，美國對於中華民國的重要性不言而喻。中華民國除了透過官方之間的接觸維持對美關係之外，同時亦使用向美國民間進行宣傳的方式，企求透過民間輿論左右美國的對華政策。然而，國府的對美宣傳政策並非一成不變，而是隨著時空環境的變遷而與時俱進。1950年代，國府依然希望能以武力「反攻大陸」，因此對美推動了「廣案」，以「共匪」作為打擊的目標，以期美國民眾可以了解「自由中國」的美好以及「共產中國」的邪惡，進而促使美國支持國府的反攻大陸計畫。然而，到了1960年代，隨著中國共產黨穩固地控制了大陸地區，國民黨政府的「反攻大陸」迷夢漸碎，與此同時，海外臺獨勢力高漲，而美國官方亦有推動臺獨的趨勢，國府遂一改過往的宣傳目標，推動「強案」，試圖打擊海外臺獨勢力，並阻止這股勢力繼續影響美國對華政策。本文將運用中央研究院以及國史館所庋藏之《外交部檔案》，比較在不同的時空背景下國府對外宣傳政策的轉變。

In 1949, due to its failure in the Chinese Civil War, the Kuomintang (KMT) collapsed like a pup tent in a gale and then retreated to Taiwan. Thereafter, the KMT-led Republic of China (ROC) which was in such disadvantaged position was mainly by the America's financial and military support to survive in the international circumstance. It was therefore without saying that the United States was of paramount importance for the ROC. The ROC, meanwhile, maintained the relations with the US not only by keeping in official touch between both governments, but also by propagandising towards the American society, in order to sway the American policy towards Chinese affairs via public opinion. The ROC's propaganda policy towards the US was not static while its policy constantly changed and adjusted in accordance with its domestic and international progress. In the 1950s the ROC still hoped to recapture mainland China via its military force; thus, the ROC launched a campaign which was called Guang an (Guang project) against ＂Communist Bandit＂ in the US. Through Guang an, the ROC expected the Americans could understand the advantages of ＂Free China＂ and disadvantages of ＂Communist China＂ in order to drive the US government to support the ROC's plan of recapturing mainland China. In the 1960s, given that the Communist Party of China firmly controlled mainland China and the dream of recapturing mainland China was far away from the reality, whilst, the overseas counterforce which underpinned the Taiwan independence movement enhanced and the US government also began to consider the possibility of Taiwan independence. For this reason, the ROC adjusted its propaganda policy and implemented Qiang an (Qiang project) to attack this counterforce as well as further impede such counterforce to continually influence US policy towards Chinese affairs. In this article, the author uses the diplomatic documents collected at Academia Sinica and Academia Historica to anaylse and compare the changes in the ROC's propaganda policy towards the US between the 1950s and 1960s.