礮臺是清代守口守岸以求「制臺灣」進而「治臺灣」的重要利器。臺島四面環海，海岸綿亙千餘里，防不勝防，故有清一代海防以臺灣府城為主。府城自古隔著臺江與安平相望，安平之南北則各有一串沙汕，沙汕間有較深之海道即船舶進出之處並置兵守之。但十七世紀以來，此地沙汕及其間港道經常變動，尤其臺江浮覆內海變陸埔之後，進出府城的門戶、要口也隨之更動，海防礮臺之設置必也隨之變動，因此，透過礮臺建置沿革之研究，正可以回顧臺灣府城在地理、地形、地貌之變化下，其海防設施有何因應調整，進而瞭解其對府城興衰之影響。

For Ching China, forts were important means to control and manage Taiwan. Surrounded by thousands of miles of seashore, Taiwan was difficult to defend; thus, Ching China put her main coast defence in Tainan, Ching's base in Taiwan. Since the 17th century, due to many changes of geographical features and topography in Tainan and its neighbor, An-ping, forts were often re-established. This paper will examine the history of the establishment of these forts, especially why and how Ching China re-established these forts, and the relationship between the rise and fall of Tainan as Ching China's base in Taiwan and the re-establishment of forts in Tainan.