Concepts of national defense strategy reflect national policies to ensure national security. National defense strategy involves two conceptual elements: defense and strategy. On the one hand, the concept of defense emphasizes the idea and posture of protection, the main purpose of which is to prevent or eliminate enemy threats. On the other hand, the concept of strategy is about planning and actions, and its main purpose is how to achieve proposed defense policies. This article examines how and how far strategic concepts of Taiwan’s national defense have been influenced by Taipei-Beijing competition for sovereignty, the asymmetry of national power of Taiwan and China, and the unique strategic perspective of successive ROC presidents. The article then argues that strategic concepts of Taiwan’s national defense have been decisively driven by one prime factor: to secure the perspective of the ROC’s sovereign status as understood by Taiwan’s leaders. Moreover, strategic concepts of Taiwan’s national defense have had variability and continuity since the 1970s, but, in general, they have three basic common characteristics: notion of defensive posture, idea of preventive deterrence, and idea of internationalized Taiwan security.