Blood glucose before dinner can be regarded as random blood glucose, normal not more than 11.1mmol/L, for diabetic patients generally need to control not more than 10.0mmol/L, it is recommended to improve the fasting blood glucose and postprandial blood glucose, a comprehensive assessment of blood glucose level. 1. Undiagnosed people: blood glucose before dinner can be regarded as random blood glucose, normal not more than 7.8mmol/L; when random blood glucose ≥11.1mmol/L, and at the same time there are “three more and one less” clinical manifestations, it can be diagnosed as diabetes mellitus. It is recommended to improve the fasting blood glucose, postprandial blood glucose, glycated hemoglobin and other related examinations to comprehensively assess the blood glucose level. 2. Diabetic patients: For diabetic patients, the glycemic control target is generally 4.4mmol/L to 7.0mmol/L for fasting blood glucose, and not more than 10.0mmol/L for non-fasting blood glucose. The glycemic control target should be set according to the individual’s situation, and can be appropriately relaxed for elderly patients in order to prevent the occurrence of hypoglycemic reaction. If blood glucose is found to be high or low, it is recommended to consult a doctor in time for targeted treatment under the doctor’s guidance.