After the Renaissance, Western countries entered a new stage of development at the end of the fifteenth century. During that time, Europe was expanding its power into other continents. In the beginning of the seventeenth century, the army of the Dutch East India Company (VOC, Vereenigde Oostindische Compagnie) invaded the Pescadores of Taiwan twice. They were defeated by the troops of the Ming Dynasty. In 1623, Dutch governor ordered to build a bamboo fortification in Tayouan (Anping). This structure existed for a very short time. The Dutch reentered the Taijiang Neihai (the Taijiang Inner Sea, an inner sea that no longer exist due to siltation) in 1624 and began their colonization of Taiwan. Forts are the most important building" types built by the Dutch. Fort Zeelandia (1624), Fort Anthonio (1644) and Fort Provintia (1653) are the most important examples. These forts were built in Western style, quite different from Chinese style city walls and city towers. The designers of these forts came from the colonists’ mother country. This paper, with an aim to reconstruct seventeenth century architectural history of Taiwan, will firstly review the architectural development in Taiwan in the seventeenth century, mainly the Dutch forts. Then, discussions will be focused on the conservation of these forts; many of them have been designated as national monuments.