Abstract: ObjectiveTo study the association of psychosocial factors with depression in middle school students and to provide bases for mental health education and psychological intervention.MethodsWith cluster randomly stratified sampling method,a total of 620 students from four middle schools were selected and surveyed with Adolescent Life Event Scale(ASLEC),Perceived Social Support Scale(PSSS),A-type Behavior Questionnaire,Anxiety Scale,and High School Students Depression Scale.The height and weight of the students were also measured in accordance with the "Physical Health Survey of Chinese Students Testing Rules".Results The detection rate of depression in the students was 27.6% (171/620)and the rate of the girls(67,46.1%)was lower than that of the boys(53.9%)but without significant difference(χ²=7.79,P>0.05).The score of depression of high school students was higher than that of middle school students with a significant difference(P<0.001).The detection rate of anxiety was 36.3% (225/620)and the rate of the junior school students was 44.4%,lower than that of the high-school students(55.6%)with a significant difference(χ²=12.46, P<0.01).The results of multiple linear regression analyses showed that health adaptation,study pressure,A-type behavior, anxiety,and body weight were independent risk factors for depression and interpersonal social support were protective factors of depression among the students.ConclusionLife event,social support,A-type behavior,and anxiety are closely related to depression among middle school students.