Abstract: Objective To investigate the relationship between adult attachment and social adaptation among middle school students.Methods With Middle School Student's Social Adaptation Scale,Chinese Adaptation of Experiences in Close Relationships Inventory,and Relationship Questionnaire,a total of 654 middle school students selected with convenience sampling from Huzhou city,Zhejiang province were tested.Results The proportion of secure,dismissing,preoccupied,and fearful attachment was 36.9%,23.5%,22.8%,and 16.8%,respectively.The proportion of secure and preoccupied attachment for high school students was significantly higher than that of junior middle school students(66.1% vs 52.9%).The proportion of dismissing and fearful attachment for junior middle school students was significantly higher than that of high school students(47.2% vs 33.9%).The gender difference in adult attachment among the middle school students was not significant.Results of Experience in Close Relationships Inventory also indicated that the score of avoidance attachment of male middle school students was significantly higher than that of female students(junior middle school students:3.54±0.75 vs 3.35±0.81; high school students:3.54±0.69 vs 3.00±0.85).The scores of secure attachment and dismissing attachment of middle school students were higher than those of preoccupied and fearful attachment in the subscales of social adaptation,such as content particularity,forecast domination,psychological adjustment,and dynamical support.The scores of avoidance attachment and anxiety attachment were significantly negatively correlated with subscale scores of social adaptation(r=-0.128——0.250).Conclusion The proportion of secure attachment in middle school students was the highest among the four kinds of adult attachment and the adult attachment was correlated with social adaptation in middle school students.