Objective:This research aimed to explore the relationship between human serum ciliary neurotrophic factor and type 2 diabetes mellitus. Methods:A total of 101 patients of type 2 diabetes mellitus were separated into three groups,including DM group(n=37),DR group(n=34),and DPN group(n=30). Twenty cases of the health examination were enrolled the control group. General information was gathered including age,gender,diabetic course,height,weight and waistline. Biochemistry,C-peptide and glycosylated hemoglobin were detected by clinical laboratory and serum CNTF level was detected by ELISA. Results:①There were no significant differences in gender,age,height,weight,body mass index and waistline between groups. Diabetic course,fasting blood glucose,glycosylated hemoglobin(HbA1c),low-density lipoprotein cholesterol(LDL-C) in the group of DR and DPN were higher than those in the DM group. The level of estimated glomerular filtration rate in the DR group was(86.03 ± 20.80) mL/min,which was remarkable lower compared to the DM and DPN group. Compared with the normal group,serum CNTF in three groups with diabetes mellitus was distinctly reduced(F=49.612,P < 0.001). ②Diabetes mellitus complicated with retinopathy and peripheral neuropathy was negatively correlated with serum CNTF by Pearson correlation analysis(r=-0.741,P < 0.001). ③The result of Logistic regression analysis showed that CNTF,HbA1C and LDL-C were independent risk factors for the development of DR and DPN. Conclusion:The level of serum CNTF was significant lower in diabetic patients,and it was negatively correlated with diabetic complications. CNTF is one of the independent risk factors for diabetic retinopathy and peripheral neuropathy.