Rumination and childhood trauma are related to depressive symptoms in clinical and non-clinical individuals. This is the first study aimed to test the mediating effect of rumination on the relationship between childhood trauma and depressive symptoms in schizophrenia patients. A total of 313 schizophrenia patients were recruited in the present study. The 17-item Hamilton Depression Rating Scale (HAMD-17) was adopted to evaluate depressive symptoms, the short-form Childhood Trauma Questionnaire (CTQ-SF) and the 10-item Ruminative response scale (RRS-10) were utilized to assess the childhood trauma and rumination in patients, respectively. Our results showed that 168 schizophrenia patients (53.67%) had comorbid depressive symptoms. These patients with depressive symptoms had higher levels of childhood trauma [both CTQ-SF total scores and emotional abuse (EA), emotional neglect (EN), physical neglect (PN) subscale scores] and rumination (both RRS-10 total scores and brooding, reflection subscale scores) compared to patients without depressive symptoms. The stepwise logistic regression analysis identified that EN (OR 1.196, P = 0.003), PN (OR 1.1294, P < 0.001), brooding (OR 1.291, P < 0.001) and reflection (OR 1.481, P < 0.001) could independently predict the depressive symptoms in schizophrenia patients. Moreover, RRS-10 and its subscale scores could mediate the relationship between depressive symptoms and childhood trauma, especially EA, EN and PN in schizophrenia. Our preliminary findings suggest that the rigorous assessment and psychosocial interventions of rumination are important to alleviate the influence of childhood trauma on depressive symptoms in schizophrenia patients.