第二次鴉片戰爭影響晚清中外往來十分深遠，自戰爭初始階段，無論英軍或是較晚來華的法軍，都十分重視蒐集和偵查中國作戰區域的水文情資，因其與艦艇航行、登陸作戰、岸上目標攻擊、後勤補給、野戰醫院布署等軍事安排皆有關聯，與火炮技術、船艦性能、戰略運用同為影響戰役的重要環節。然而，學界對此議題既有研究仍較為片斷，主要僅集中於特定戰役或地圖繪製等面向。本文依照時序發展，一方面嘗試較為完整地構建英法聯軍在戰爭不同階段水文偵蒐的過程，同時著重於幾個議題：一是在歐洲軍事情報偵蒐專業化的脈絡下，討論執行水文量測任務官兵所受的專業教育、戰場上使用的量測儀器與方法；其次則是聯軍蒐集水文情報的管道、偵蒐的著重點、情報的解讀；最後探討聯軍如何將水文情資與作戰其他環節相互聯結，以利判斷戰場情勢或取得戰場優勢，從而理解水文偵蒐在這場戰役扮演的角色。

The Second Opium War exerted a profound impact on the relations between Chinese and the foreign powers in the late Qing Dynasty. From the initial stage of the war, both the British army and the French army, which arrived later, attached great importance to the collection and detection of hydrographic information of the Chinese combat zone, as it was related to military arrangements, such as navigation of ships, landing sites, attacks on shore targets, logistic supplies, deployment of field hospitals, etc. Hydrographic information played an important role in the battles along with artillery technology, ship performance, and strategic use. Although military arrangements are related to artillery technology, ship performance, and strategic use, studies on this topic to date remain rather fragmentary, mainly focusing on specific battles or map production. On the one hand, this paper attempts to construct a more complete picture of the hydrographic acquisition process of the British and French allied forces during different stages of the war in accordance with the chronological development while focusing on several questions to achieve a better understanding of the role played by hydrographic acquisition in this war: (1) What professional education did the officers and soldiers receive in hydrographic measurement missions? (2) What measurement equipment and methods were used on the battlefield in the context of the professionalization of military intelligence gathering in Europe? (3) Through what channels did the coalition forces collect hydrographic intelligence? (4) What was the focus of the acquisition and interpretation of intelligence? (5) How did the coalition forces link hydrographic information with other elements of warfare to help judge the battlefield situation or gain an advantage on the battlefield?