This paper mainly explores a set of seven old Chinese plans of Weihaiwei in the Russian State Library, including The Weihaiwei Complete Map and six plans of coastal artillery forts. These plans are the only large-scale official maps of Weihaiwei forts made by the Qing government before the Sino-Japanese War in 1894 and were probably captured by a Russian consulate official K. I. Dmitriev during the occupation of Tianjin by the Eight-Nation Alliance in 1900. The plans were sent to the Oriental Institute in Vladivostok and later transferred to the Lenin State Library of the USSR in Moscow in 1939, where they were stowed until present. This collection is significant for studying the Beiyang fleet and coastal defense engineering in the late Qing period. In addition, this paper also presents three rare colorful manuscript copies of Sa Chengyu's Illustrations of the North and South Sea Artillery Forts kept in Russia and China. Several other millitary plans relating to Weihaiwei from the Sheng Xuanhuai archive in the Shanghai Library, the archives of the National Institute for Defense Studies, and Imperial Household Agency of Japan are also discussed.