¡¾Abstract¡¿ AIM: To evaluate the characteristics of the social support, and to analyze the relationship between social support, personality and mental health in the military personnel stationed on islands. METHODS: Perceived Social Support Scale (PSSS), the Symptom Checklist 90 (SCLª²90) and the Eysenck Personality Questionnaire (EPQ) were used to investigate 203 military personnel stationed on islands, and 396 military personnel stationed on land investigated with the same questionnaire were used as control. RESULTS: The social support of the military personnel stationed on islands was significantly poorer than that of the military personnel stationed on land (P<0.05). Significant difference was found in all the symptom factors except the panic factor at the three social support levels in the military personnel investigated (P<0.05). Significant difference was found by EPQª²E and EPQª²N (P<0.05). The higher the social support, the better the mental health. The lower the score of EPQª²N, the higher the score of EPQª²E. There was negative correlation between the social support and most factors of SCLª²90. The social support had significant positive correlation with EPQª²E (r=0.322), but no significant correlation with EPQª²N. CONCLUSION: Social support plays an important role in mental health. The extravert or introvert personality has close relation to acquisition, utilization and perception of the social support, which may be one of the major factors that affect the social support level. ......