In 1867, Deng was accepted into the Naval Academy (船政學堂) in Mawei, Fujian, as part of the first batch of students. After completing seven years of education – five years of theoretical learning, and two years of practical training on board the "Jianwei" (建威) – he graduated from the Naval Academy in 1874 with excellent results, and impressed Shen Baozhen, the Naval Minister in the Qing government. Upon Deng's graduation, Shen assigned Deng to the Fujian Fleet and appointed him as the "bangdai" (幫帶; equivalent to Commander) of the scout transport boat "Chenhang" (琛航). In the following year, Deng was promoted to serve as the "guandai" (管帶; equivalent to Captain) of the gunboat "Haidongyun" (海東雲). In May 1874, when the Japanese invaded Taiwan, Deng was ordered to lead Qing forces to reinforce the defences at Keelung and the Pescadores. He was also appointed as "qianzong" (千總; seven ranks below "tidu").