Abstract Purposes Although few researches have examined the cognitive mechanisms for the effect of childhood psychological maltreatment on depression, childhood history of psychological maltreatment is a risk factor for depression. The purpose of the study is to explore the relation among automatic thoughts, depression and the psychological maltreatment they had suffered in childhood. In this study, automatic thoughts were proved to be mediators. Methods Cluster sampling was applied in this study while 838 junior high school students were chosen from countryside of Heilongjiang Province as subjects. Childhood Psychological Maltreatment Scale, Automatic Thoughts Questionnaire (ATQ) and Self-Rating Depression Scale (SDS) were applied in this investigation. The statistical analyses were performed with SPSS 17.0. The reliability of the scales was tested with Cronbach’s Alpha. And the relation among childhood psychological maltreatment, automatic thoughts and depression was tested with Structure Equation Modeling. Results (1) The Cronbach’s Alphas of three scales were 0.72-0.95 in the study, acceptable coefficients. (2) In the investigation, 44.28% of the junior high school students had been maltreated in their childhood while terrorizing was the most common type of psychological maltreatment. (3) The study showed there were significant gender differences (P<0.001) in psychological maltreatment score. (4) The descriptive statistics for the main variables were presented in this study. The correlation matrix showed that automatic thoughts and depression were significantly correlated with psychological maltreatment (P<0.001). (5) Childhood psychological maltreatment had significant direct effect on automatic thoughts and depression (β=0.245, β=0.674, both p<0.001), and automatic thoughts had significant direct effect on depression (β=0.383, p<0.001). It was proved that automatic thoughts was a partial mediator between childhood psychological maltreatment and the depression of the children (Z=51.2, p<0.01). Conclusions (1) The childhood psychological maltreatment scale, ATQ and SDS had good reliability in the study. (2) The childhood psychological maltreatment was common in the investigated sample, and 44.28% of the junior high school students had been maltreated, terrorizing being the most common type of maltreatment. (3) The effects of childhood psychological maltreatment and automatic thoughts of junior high school students on their depression were proved in this study. The participants with a childhood history of psychological maltreatment reported higher level of depressive symptoms than those who had no experience, and this aggravation of depression was mediated by automatic thoughts. The mediating roles of automatic thoughts suggested salient leverage points for changing cognitive mechanisms reformation to decrease the depression level of junior high school students. Innovation Previous researches have proved the relationship between childhood psychological maltreatment and depression. Despite this, the study’s results support the proposal that negative cognition plays a particularly important role in the development of depression in children who experienced psychological maltreatment. In addition, this study illustrates that automatic thoughts are likely to be important targets for intervention in children who experienced psychological maltreatment. The children can be taught to think in the way that is good for their recovery from childhood psychological maltreatment.