Abstract： Objective To investigate the features of negative automatic thinking among military personnel stationed on the island and also to analyze related influencial factors.Methods Assessment was performed among the military personnel stationed on the island and ashore by using automatic thinking scale,perceived social support scale and social stress scale,then,the relationship between negative automatic thinking and perceived social support and psychological stress was analyzed in the study.Results The detection rates of automatic thinking,perceived social support and psychological stress among the military personnel stationed on the island were all obviously higher than those of the military personnel working ashore.(P ＜ 0.05 or P ＜ 0.01).The total scores of automatic thinking and stress in the military personnel working on the island were all higher than those of the people working ashore (P ＜ 0.05).There were significant differences in total scores of various scales,when comparisons were made between commissioned officers of the 2 groups (P ＜ 0.05).Differences could only be seen in external family support and stress scores among commissioned officers.Total scores of internal family support and perceived social support of commissioned officers were all lower than those of the non-commissioned officers,but the scores of automatic thinking were higher than those of the non-commissioned officers (P ＜ 0.05).Pearson analysis showed that negative automatic thinking was positively correlated with psychological stress (r =0.292,P ＜ 0.05),however the scores of perceived social support were negatively correlated with the scores of various dimensions (r =-0.540 -0.672,P ＜ 0.05).Stepwise regression analysis indicated that perceived social support partially mediated the relationship between psychological stress and negative automatic thinking,and the mediating effect accounted for 30.9％ of the total effect.Conclusion Negative automatic thinking among the military personnel stationed on the island was on the whole not optimistic,and its influential factors included psychological stress and low social support.Psychological stress could affect negative automatic thinking of the military personnel stationed on the island directly or indirectly by mediating effect.Active and effective family and social support,rational psychological counseling and training were beneficial to the alleviation of negative thinking and the improvement of the physical and mental health of the military personnel stationed on the island.