國軍在一九五零年的登步─舟山之役與隨後的大撤退，實為國共內戰重要的轉捩點，成功扭轉國軍戰末期屢屢陷在戰敗與崩潰的困境。舟山為臺灣之右臂，戰略位置重要。蔣中正在淞滬撤退後，進行舟山群島之駐防與部署。從隨後大榭島、金塘島、登步島等戰役，可以顯示國共雙方的備戰情形及其對舟山外圍島嶼的思維與攻防。登步島戰役勝利的歷史意義除了確保了舟山安全，更重要的是展現國軍英勇犧牲作戰精神與提升國軍士氣。而海空軍執行關閉政策及協同作戰，也達到封鎖東海岸港口與延緩共軍備戰速度。此論文同時探討舟山撤退的理由、規畫、經過、成果，以及自舟山撤退後之國軍在臺整編情形，以完整呈現國軍這次重要的舟山行動。; The Battle of Dengbu-Zhoushan 1950 and the following full-scale retreat of the National Army was a turning point in the Chinese Civil War, successfully reversing the situation that had seen the National Army suffer a series of defeats and near collapse in the later stages of the war. As the right arm of Taiwan, Zhoushan was of great strategic importance. After the retreat from Shanghai, Chiang Kai-shek garrisoned the Zhoushan Islands. The battles of Daxie, Jintang and Dengbu islands that followed show the battle preparedness of the two sides, their thinking towards Zhoushan's outlying islands and defense/attack strategy. The historical significance of the victory at the Battle of Dengbu Island is that, as well as ensuring the security of Zhoushan, more importantly; it showed the bravery and sprit of self-sacrifice of the National Army and raised morale. Also, the exclusion policy enforced by the Nationalist navy and air force and coordinated operations achieved the sealing off of ports on the east coast of China and delayed the Communists' battle preparations. This paper also examines the reasons for the retreat from Zhoushan, the planning, the process, results, and the reorganization of the National Army in Taiwan after the retreat to provide a full picture of this important of Zhoushan action of the National Army.