Abstract: Objective To explore the diagnostic value of prehepatic fat thickness in patients with diabetes complicated with metabolic syndrome. Methods Clinical data about 147 diabetic patients who were treated in outpatient department of joint service in Ji'nan Military Region and General Hospital of Ji'nan Military Area from March 2016 to March 2018 were collected. Patients were divided into simple diabetes (DM) group and diabetes complicated with metabolic syndrome (DM & MS) group. Data including gender, age, TC, LDL, waist circumference, BMI and prehepatic fat thickness were compared between the two groups. The prediction value of prehepatic fat thickness, waist circumference and their combination for MS was evaluated by ROC analysis. Results The total cholesterol, waist circumference, BMI, proportion of patients with family history, and hepatic fat thickness in the DM & MS group were significantly higher than those in the simple DM group (all P＜ 0.05). In male patients, the area under the ROC curve was 0.856, 0.755, and 0.920 for the hepatic fat thickness, waist circumference, and their combination, and they were 0.868, 0.754, and 0.917 for female. Conclusion Prehepatic fat thickness can be used as an indicator for the diagnosis of diabetic metabolic syndrome.