Abstract: Objective To investigate factors affecting the mental health status in military personnel stationed on Xisha Island and to suggest appropriate countermeasures against those influential factors encountered. Methods SCL -90 was used to measure the mental health status of the 420 military personnel stationed on the Xisha Island and the 450 military personnel of a certain inland naval unit. Then, a comparison was made between the 2 groups concerning mental health status. Results Mental health problems existed to a more or less extent among naval officers and soldiers stationed on the Xisha Island, and symptoms, such as depression, in whom the incidence of depression, anxiety, fear, insomnia and anorexia were more prominent in island garrison troops, when a comparison was made between them ( P < 0.01 ). Conclusions Main factors affecting the mental health status included personal identity, educational background, source of recruitment, the length of service on the island, etc. To alleviate the mental health problems among officers and soldiers stationed on small islands and to enhance combat effectiveness of the units, following countermeasures were proposed: intensifying mental health education among island garrison units, more strict psychological screening in recruits, enhancing the capability of first medical care responders in the diagnosis and treatment of psychological problems, improving the living conditions on islands and enriching their spiritual and cultural life.