Objective To investigate the diagnostic value of susceptibility weighted imaging ( SWI) in patients with mild traumatic brain injury(MTBI).Methods From June 2016 to October 2017,a retrospective analysis of 89 patients with MTBI (Glasgow score 13 to 15) in the First People's Hospital of Xiaoshan District was conducted.All patients were given head CT ,MRI and SWI within 1 week after admission.Combined with CT and phase diagram ,after removing blood vessels ,calcification and skull base artifact ,the low signal intensity on the SWI was cerebral contusion and hemorrhage.The sites,the number and the size of lesion detected on CT ,MRI and SWI images were recorded and analyzed with clinical symptoms.Results According to the presence or absence of clinical symptoms in the group ,the detection rates of microbleeds hemorrhage in patients with traumatic cerebral by SWI were 94.4%,54.2%,100.0%, 95.5%,respectively,which were higher than those by CT (16.6%,4.2%,15.0%,4.5%) and MRI conventional sequences(33.3%,8.3%,20.0%,13.6%),the differences were statistically significant (χ2＝6.633,P＝0.010;χ2＝4.260,P＝0.039,all P ＜0.05),especially in MTBI patients with a history of transient coma or persistent clinical symptoms after trauma(the detection rate was 100.0%).Conclusion Compared with conventional CT and MRI,the micro-contusion and small hemorrhagic lesions of SWI is more accurate and important in the diagnosis of MTBI,and has a significant prognostic value for clinical treatment and judgment of patients with MTBI .