河南四鎮在北魏與南朝對峙期間，一直是雙方爭戰的焦點，因此形成所謂的戰爭熱區，何方佔有四鎮，便容易形成戰略優勢。南朝據之，可以黃河為天險抗拒北魏；北魏佔之，黃河便不再是魏軍渡河的阻礙，且可以四鎮為南伐的前進據點。四鎮在劉宋初年全部屬於劉宋，之後遭北魏併吞，此後北魏即長期控有四鎮。而南朝為了挽回戰略劣勢，歷代均為爭奪四鎮與北魏爆發戰爭，雖曾奪回四鎮，但總是短暫的佔有，不久後又遭北魏奪回。本文以北魏與南朝在四鎮的戰爭為基礎，首先分析四鎮的地理形勢，說明其周遭山河、關隘等分布情形，接著詳述北魏與南朝環繞在四鎮的戰爭，透過雙方交戰的過程，解析四鎮對南北雙方各自的軍事價值及其在南北分裂時期的戰略地位。

In the North Wei and Southern dynasties, the four towns in Henan had always been the focus of the fighting between the two sides. Thus the four towns formed a so-called hot war zone. Whoever occupied the four towns will have a strategic advantage. When the Southern dynasties occupied the four towns, they could take the advantage of the Yellow River as a natural barrier to resist the North Wei; when the North Wei occupied the four towns, the Yellow River will no longer be a hindrance for North Wei crossing the river. Instead, the North Wei can use the four towns as a forward base to attack the South. The four towns all belonged to Liu Song in the early years of Liu Song. Later they were annexed by the North Wei, since then the long-term control of four towns in the hands of the North Wei. To restore the strategic advantage, the Southern dynasties attacked the four towns, although they had recaptured the towns four times, but their possession of the towns was very short, since the North Wei recaptured the towns again. Exploring the four towns against the background of wars between the North Wei and Southern dynasties, this studyfirst analyzes the geographical positions of the four towns, indicating their surrounding mountains and rivers, fortress and other distribution situation, describing the wars taking place between the twowarring parties and examining the military value and strategic position of the four towns to both parties.