Objective To analyze the value of serum C-peptide combined with glycosylated hemoglobin test in the di-agnosis of diabetes.Methods A total of 86 patients with diabetes admitted to Taixing Hospital of Traditional Chinese Medicine from January 2022 to June 2023 were selected as the observation group,and 86 healthy people who under-went physical examination during the same period were selected as the control group.Serum C-peptide and glycated hemoglobin were tested to compare the test results and diagnostic efficacy.Results The detection level of serum C-peptide in the observation group(0.83±0.23)μg/L was lower than(1.49±0.44)μg/L in the control group,and the de-tection level of glycosylated hemoglobin(9.27±1.15)%was higher than(5.74±0.62)%in the control group,and the differences were statistically significant(t=12.328,25.056,both P<0.05).The sensitivity,specificity and accuracy of the combined test were 97.67%,96.51%and 97.09%,respectively,which were higher than that of the single test,and the differences were statistically significant(all P<0.05).Conclusion The levels of serum C-peptide and glycosylated hemoglobin in diabetic patients were significantly different from those in healthy people,and the diagnostic efficacy of combined test was higher.