High glycosylated serum protein suggests that the blood glucose level is not good in the last 2~3 weeks, and there is a possibility of diabetes mellitus, but high glycosylated serum protein is not the basis for the diagnosis of diabetes mellitus, and the diagnosis of diabetes mellitus needs to be combined with the clinical symptoms and the blood glucose level. The diagnosis of diabetes mellitus is based on the typical symptoms of “three more and one less” (drinking more, urinating more, eating more, and losing weight), plus the measurement of venous plasma glucose ≥11.1mmol/L, fasting blood glucose ≥7.0mmol/L, or 2-hour glucose ≥11.1mmol/L after glucose tolerance test, which can be diagnosed as diabetes mellitus if one of them meets the diagnosis of diabetes mellitus. A diagnosis of diabetes mellitus is made when one is met. When high glycosylated serum protein is detected, it is recommended to consult a doctor in time for diagnosis by a medical professional.