明初剛值建國，福建便和東南邊海各省相似，遭受倭寇的侵擾。如何去防禦倭寇，一開始，便成為明初海防問題的重點所在。為此，洪武帝除曉諭日本國王、造船禦倭和派兵出海捕倭外，並大舉地推動海禁政策，透過「不得違禁下海」的相關規定，嚴格限制海上販貿的活動，藉以斷絕國人勾通倭盜的機會。其次，更運用「墟地徙民」的措施，透過強制遷徙海中島民的方式，來翦除元末殘餘黨盜勢力並斷絕其聲息奧援的力量，藉此達到徹底摧毀海中島嶼，作為私通倭寇的基地、藏匿海賊的窟穴，以及提供物質、訊息等的多重角色。雖然，「墟地徙民」強迫海中島民遷入內地，十分地無情，但若是站在海岸防禦的角度來看，「墟地徙民」的措施是有其價值的。因為，它可盡量地斷絕入侵的倭、盜中途休息、藏匿、補給和訊息取得的機會；而且，淨空的島嶼遠比島上有居民棲居來得容易掌握狀況。此次「墟地徙民」是全面性的，福建地區實施的對象不僅只有瀕海地區和近海島嶼而已，連海外的澎湖亦在其中。另外，為徹底根絕倭患的問題，並配合海禁和「墟地徙民」的實施，明政府亦在福建沿海推動一連串的海防建設計劃，諸如按籍抽兵、增設衛所巡司、擘建水寨……等，這些艱鉅的工作，多由江夏侯周德興來負責執行。其中，又以水寨的擘造最具創意，一因水寨兵船巡防海中，衛所巡司捍衛岸上，一以制海，一以控陸，相輔相成。二因「墟地徙民」讓沿海島民回到岸上，設立水寨則讓戍軍由岸上來到海島，「島民進內陸、寨軍出近海」，兩者相互交替，藉以增強海上禦倭工作的進行。

When the Ming dynasty was just established, Fukien facing the same problem as other south-eastern maritime provinces was disturbed by the piracy. In the early Ming dynasty, how to defend the pirates was the point of coastal defense. For that, Emperor Hong-Wu did not only write to the king of Japan, but also built Navy to arrest the pirates. Further he promulgated a series of prescript about blockade on the coastal water. The ban on marine activity confined the seaborne trade stringently, and it deterred people from colluding with the pirates. Besides the prescript of "Withdrawal from Islets" forced islanders to emigrate from seashore to hinterland. By the way, it did not only reduce the power of the rump of Yuan, but also prevent the islets becoming the bases of the pirates and the sources of material and information. Although it is absolutely ruthless to force islanders to emigrate from seashore to hinterland, on the strategic hand the prescript of "Withdrawal from Islets" plays an important role in coastal defense. It can prevent the pirates taking a midway rest, skulking and getting any material or information when they made incursion. Besides it is much easier to take command of the desolate islets. Consequently it was conducive for the navy to performing assignments that the Ming government endeavored to prevent the collaboration between the islanders and the pirates. Besides, the navy could take proper reaction when the pirate made incursion.