BackgroundNot all adolescents who have endured childhood trauma will develop depressive symptom, nor will they all experience the same level of depressive symptom. According to previous research, cognitive emotion regulation strategies may explain a portion of the variance. Observe the connection between childhood trauma and depressive symptom and investigate whether cognitive emotion regulation strategies mediate or moderate this association.MethodsIn October 2019, a cross-sectional study measuring childhood trauma, cognitive emotion regulation strategies, and depressive symptom among Zhuang adolescents was done in one senior high school and two junior highs in Chongzuo, Guangxi, China, using a self-report questionnaire. To examine the hypothesis of mediating and moderating effects, SPSS PROCESS was utilized.ResultsIn this study, there was a positive relationship between childhood trauma and depressive symptom, whereas there were positive correlations between expressive suppression and childhood trauma and depressive symptom (r = 0.380, 0.246, and 0.089, respectively, p < 0.01). The 5,000-sample bootstrap procedure revealed that the indirect relationship between the independent variable (childhood trauma or emotional abuse) and the dependent variable (depressive symptom) was statistically significant (β = 0.0154 95% CI: 0.0019, 0.0165, β = 0.0442 95% CI: 0.0008, 0.0117). The statistical significance of the interaction effect enhanced the R-square value of the moderating effect when the independent variable was the total childhood trauma score (ΔR2 = 0.0044, 0.0089).ConclusionsOur findings corroborated the conclusion of prior research that cognitive emotion regulation strategies mediate and moderate the development of depressive symptom. Although we demonstrate that cognitive emotion regulation strategies play a mediating and moderating role in the relationships between childhood trauma and depressive symptom, the mediating effects on the relationships between the other types of childhood traumas, including physical abuse and neglect, sexual abuse, emotional neglect, and depressive symptom, did not emerge.