〔Abstract〕 Objective To investigate the clinical value of serum C peptide and hemoglobin in diabetic patients. Methods 120 diabetic patients admitted by Yangchun People's Hospital from May 2019 to May 2020, and 120 health examiners were selected as control groups. They tested hemoglobin and serum C peptide through type TOSOHHLC–723G8 and Siemens ADVIA Centaur XP to compare the test results of the two groups. Results Compared with the control group, higher hemoglobin, lower serum C peptide, and significant differences (P < 0.05). Conclusion Combined testing of serum C peptide and hemoglobin levels can provide reference for the early diagnosis of diabetes.