民國（以下同）38年8月，國共內戰已近尾聲，國民政府為穩定東南各省局勢，統一軍事與政治事務之指揮，乃在臺北成立東南軍政長官公署，由臺灣省主席陳誠擔任公署長官。7個月的時間，期間經歷廈門、古寧頭、登步島等重大戰役，可謂國民政府撤退來臺過程中，軍事上最為緊張的階段。東南軍政長官公署為堅守東南沿海島嶼、防止中國共產黨軍隊（以下簡稱共軍）渡臺、鞏固臺灣為最後基地，曾制訂「東南區作戰計畫」、「臺灣海峽海空軍搜索警戒計畫」等重要計畫，相關文件現存檔案管理局。本文由檔案分析作戰計畫的目的與內容，及計畫修改的原因，並由公署聯席會議紀錄，分析計畫在實行上的成效與困難。

When the Chinese civil war almost ended up in August, 1949, the KMT government established the Southeast Military and Political Executive Office in Taipei in order to unify the command of both military and political affairs and assigned Chen Cheng as the executive officer. While the KMT government retreated to Taiwan, it has suffered the most tense battle during seven months such as Xiamen, Guningtou and Tengbu island. To defend the islands along the southeast coast, prevent communist troops and consolidate Taiwan as the fundamental base, the Office formulated plans such as "The battle plan in southeast area", "Marine and air force search & alert plan in Taiwan Strait", which are now preserved in National Archives Administration. This article analyzes the purpose and details of these battle plans and the reasons for adjustment, then evaluates the effectiveness and difficulties of these plans through the joint meeting minutes made by the Office.