The normal value of blood glucose for 65-year-old people is 3.9~6.1mmol/L for fasting blood glucose and less than 7.8mmol/L for 2 hours after meal. For 65-year-olds without diabetes, the standard of blood glucose is the same as that of normal people of other ages, with fasting blood glucose of 3.9-6.1mmol/L and 2-hour postprandial blood glucose of less than 7.8mmol/L. However, as 65-year-olds age, the function of the pancreas can gradually decline, and blood glucose of 65-year-olds is prone to exceeding the normal range. Diagnostic criteria for diabetes mellitus: diabetes mellitus can be diagnosed when fasting blood glucose ≥7.0 mmol/L, or 2-hour post glycemic load blood glucose ≥11.1 mmol/L, or random blood glucose ≥11.1 mmol/L, accompanied by three more and one less symptom (drinking more, eating more, urinating more, and weight loss). It is recommended that the elderly monitor their blood glucose and make a definitive diagnosis under the guidance of a doctor if necessary.