Objective To evaluate the relationship between newly developed depression after mild traumatic brain injury (mild-TBI)and abnormality on susceptibility-weighted imaging (SWI).Methods One hundred and eighty patients after mild-TBI,who had normal findings at conventional CT and MRI were enrolled in our study.All cases underwent conventional MRI and SWI.Ac-cording to SWI,the number and volume of microbleed lesions were calculated.All patients were followed up within 1 year after TBI,and divided into depressive group and non-depressive group based on SCID-IV.The difference in microbleed lesions on SWI was compared between the depressive group and non-depressive group.Results The incidence rate of microbleed on SWI in depres-sive group was higher than that in non-depressive group (P < 0.001 ).Among patients with microbleed lesions,the volume and number of lesions in depressive group were more than those in non-depressive group (P <0.001),and these differences were only found at the frontal,parietal and temporal lobes (P < 0.001 ).No significantly difference between depressive and non-depressive group was found in other areas (P >0.05).Conclusion SWI is useful to identify the microbleed lesions after mild TBI.The depres-sion after TBI is correlated with the location and distribution range of microbleed lesions.