Objective：To investigate the relationship between serum adropin and carotid atherosclerosis in patients with type 2 diabetes mellitus（T2DM）. Methods：A total of 108 T2DM patients were divided into two groups based on the results of carotid color Doppler ultrasound： 68 with carotid atherosclerosis（T2DM+CAS group）and 40 without carotid atherosclerosis（simple T2DM group），and 60 healthy volunteers were enrolled as normal control（NC group）. General information was gathered. Biochemistry，glycosylated hemoglobin A1c（HbA1c） and fasting insulin（FIns） were detected by clinical laboratory. Serum adropin concentration was measured by enzyme-linked immunosorbent assay. Results：The levels of adropin in T2DM+CAS and simple T2DM were significantly lower than that in NC（P＜0.01）.There was no significant difference of the adropin concentration between T2DM+CAS group and simple T2DM group. Adropin level was negatively correlated with body mass index，triglycerides，fasting plasma glucose，FIns，homeostasis model assessment of insulin resistance（HOMA-IR），HbA1c，high-sensitive C reactive protein and positively correlated with high-density lipoprotein cholesterol（all P＜0.01）. Multiple linear regression analysis revealed that FIns and HbA1c were independent influencing factors of serum adropin（all P＜0.01）. Conclusion：Serum adropin levels were significantly reduced in patients with T2DM，which may be closely related to the pathological process of T2DM by regulating insulin sensitivity，lipid metabolism and inflammatory responses.