Due to the extremely challenging climate of the Gulf of Aden and the complicated hygiene conditions of the surrounding countries, the soldiers of PLA Navy escort fleets are easily vulnerable to various regional infectious diseases. It is quite onerous to implement the plague controlling mission. This report described a case of hepatitis A virus infection during an operation of PLA Navy escort fleet on the sea in the Gulf of Aden area, introducing the basic symptoms, main management methods, and putting forward the countermeasures and recommendations from the perspective of infectious disease control and prevention on the sea.