本論文探討美國對中國政策的轉變，透過新古典現實主義理論來解釋轉變原因。中美正式交往40年「經濟」為主要交往內容，然而隨著中國經濟發展，人民的自由受到限制，造成美國對中關係的轉變。由過往的美國外交對中國擴張交往政策是主流，川普時期演變成全面性競爭，川普執政時期「美國優先」、「讓美國再次偉大」、「印太戰略」為主要的內容。論文深入分析川普時期美國對中國的科技政策變化以及其原因，主要集中在國家安全、經濟利益與科技優勢的考量。川普政府對國家安全的重視以及科技優勢的保護，使得其對中國的科技政策轉向強硬。對於理解美國當前的政策立場以及預測未來美中關係具有重要意義。

This thesis examines the transformation of the United States Policy towards China and interprets this transformation through the lens of Neoclassical Realism. Over 40 years of formal Engagement between the U.S. and China, “Economic” interactions have been the primary focus. However, with China's economic development, concerns have arisen about restrictions on human freedoms, leading to changes in the U.S.-China relationship. In the past, the mainstream approach of U.S. foreign policy towards China was characterized by expanding engagement and seeking economic cooperation and dialogue. However, during the Trump administration, this approach evolved into one of comprehensive competition, driven by the principles of “America First,” “Make America Great Again,” and the promotion of the “Indo-Pacific Strategy.” The thesis delves into an in-depth analysis of the changes in U.S. technology policy towards China during the Trump era and identifies key factors such as considerations of national security, economic interests, and technological advantages. The emphasis placed by the Trump administration on National Security concerns and protecting technological advantages resulted in a more assertive stance towards China in the realm of Technology Policy. Understanding the current policy stance of the United States and predicting the future of U.S.-China relations hold significant importance.