大英圖書館典藏一幅清代臺灣地圖，紙本彩繪，橫幅長卷。圖中最顯著的人文景觀是縱貫臺灣南北的紅線與藍線番界，另有交通路線、府縣官署、綠營汛塘、關隘與望樓，以及原住民的番社、漢人的街庄等描繪。由於此圖缺乏圖題、圖說，有關此圖之主題、繪製年代及繪製者等問題，仍待討論。本文除了針對此一圖像進行資料介紹外，並引述相關學者對於此圖的研究與討論；在前述基礎上，依據相關文獻，探討此圖之繪製年代、敘事思維及資料來源。本文認為此圖有關臺灣南部鳳山縣土牛、關隘的描繪，反映的是1778-1780年（乾隆43-45年）時的變化，因此年代應在1780年或稍後。此圖之內容與敘事思維均涉及綠營武備，同一時期臺灣鎮總兵董果可能與此圖之繪製有關。另外，本圖對於鳳山縣沿山地區的描繪與蔣元樞編撰《重修臺郡各建築圖說》的記載不同，本文探討其異同，並討論鳳山縣部分關隘的移徙與存廢問題。

The British Library collection contains a spectacular map of Qing Taiwan during the Qianlong era. It is in color and spans approximately 490 cm in length. From a cultural and historical perspective, the feature that warrants the most attention in this cartographic depiction of Taiwan is the changing administrative borderlines (番界, fanjie). Moreover, this map sketches also both imperial and unofficial infrastructure, including traffic routes, governmental offices, military posts (汛塘, xuntang), frontier inspection stations (關隘, guanai), local watchtowers (望樓, wanglou), aboriginal villages (番社, fanshe), as well as Han towns and settlements. This map of Qianlong era has neither captions nor textual descriptions, thus requiring a more thorough reconstruction of its historical background, important themes, the main initiator and his chief intentions. This paper seeks to answer these questions according to the relevant literature and documentation. In view of the specific watchtower depictions, which reflect changes taking place between 1778 and 1780, the map was drawn around or after 1780. Furthermore, this map is probably also related to General Dong Guo (董果), who at that time was in charge of the Taiwan garrison. Taiwan subsequently emerged as a crucial part of Qing empire's southern frontier and central channel to the outside world in the imagination of Qing officials in the second half of the eighteenth century. This Taiwan map of Qianlong era stored at the British Library Collection sheds light on the attitudes of Qing dynasty officials regarding the marine frontier.