Abstract: Objective To explore the incidences and characteristics of common diseases in the crew of the instrumentation ship during a voyage, and provide improved strategies for medical security. Methods The incidences of common diseases in crews of an instrumentation ship from December 2017 to February 2018 were investigated and analyzed, and its possible reasons were analyzed. Results Totally 300 crew members were enrolled in this study, including 292 males and 8 females, aged from 18 to 60 years, with an average age of 39 years. The top five diseases of the ship's crew were upper respiratory tract infection (35.33%), dermatosis(22.33%), oral ulcer (14.67%), training injury (14.33%) and gastrointestinal disease (13.67%). Conclusion As the incidences of upper respiratory tract infection, skin disease, oral ulcer, training injury and gastrointestinal disease are high, drug reserve, preventive measures and health education of related diseases are recommended before voyage.