The blood glucose criteria for type 2 diabetes are: fasting blood glucose ≥7.0mmol/L, or two-hour postprandial blood glucose ≥11.1mmol/L, or random blood glucose ≥11.1mmol/L, or glycated hemoglobin ≥6.5%, meeting any one of these criteria and accompanied by symptoms of diabetes. Typical symptoms of type 2 diabetes mellitus are “three more and one less”, i.e., drinking more, eating more, urinating more, and weight loss, but also symptoms such as fatigue, sleepiness and tiredness, and mental depression. When suffering from complications or concomitant diseases at the same time, it can also show corresponding symptoms, such as blurred vision, foamy urine, numbness of hands and feet. The diagnosis of diabetes mellitus is mainly based on blood glucose levels: fasting blood glucose ≥7.0mmol/L, or two-hour postprandial blood glucose ≥11.1mmol/L, or random blood glucose ≥11.1mmol/L, or glycosylated hemoglobin ≥6.5%, and any of them with diabetic symptoms will lead to diabetes mellitus diagnosis. Compared with type 1 diabetes, type 2 diabetes occurs more often in obese people, and most often in middle-aged and elderly people, usually with insulin resistance, which can be identified by insulin function, autoantibodies and other related tests. When blood glucose is abnormal, it is necessary to consult a doctor in time for observation and standardized treatment under the guidance of a clinician.