To study the clinical characteristics in patients diagnosed with lateral medullary syndrome in both negative and positive diffusion weighted imaging (DWI) patients. Methods: Patients given the diagnosis of lateral medullary syndrome from February 2012 to December 2017 in Wuhan Tongji Hospital were retrospectively studied. Patients were divided into the DWI-negative group and DWI-positive group based on brain MRI results. Baseline data, clinical presentations, laboratory and image findings, and prognosis were compared between the two groups. Results: Of the 43 patients with lateral medullary syndrome recruited to the study, 34 were DWI-positive and 9 (20.9% ) were DWI-negative. No significant difference was found in age, gender, histories of hypertension, diabetes mellitus, smoking, stroke, and clinical symptoms between the two groups (P>0.05). No significant difference was found in blood glucose, Hb1AC, LDL, HDL, UA, stenosis or occlusion rate of responsible blood vessels, and stroke recurrence rate between the two groups (P＞0.05). The diastolic blood pressure at the time of admission and HCY level in DWI-negative patients were significantly lower than those of DWI-positive patients (P<0.05), and the duration from disease onset to DWI screening performance was significantly shorter in DWI-negative patients than in DWI-positive patients (P<0.05). Conclusion: The levels of diastolic blood pressure upon admission and HCY in DWI-negative patients were lower than those in DWI-positive patients. The duration from onset to DWI screening in DWI-negative patients was shorter than that in DWI-positive patients.