Diabetes mellitus is now a very common chronic disease, how to diagnose diabetes mellitus in the clinic, according to the current World Health Organization standards, mainly from the following aspects: 1, patients with typical symptoms, that is, there are obvious three more and one less, polyphagia, polyphagia, polyuria, wasting, as long as fasting blood sugar > 7.0mmol/L, or OGTT 2 hours blood sugar > 11.1mmol/L, or random blood sugar measurement blood sugar ＞If the fasting blood glucose > 7.0mmol/L, or OGTT 2 hours blood glucose > 11.1mmol/L, or random blood glucose measurement > 11.1mmol/L, as long as there is 1 item to meet the standard, diabetes can be diagnosed; 2. It is necessary to measure blood glucose again at another time. If the blood glucose exceeds the standard for more than 2 times, it can also be diagnosed as diabetes. 3. In patients without any symptoms, when doing the glucose tolerance test, if the blood glucose is measured 2 hours after taking 75g of glucose orally, and if the blood glucose is >11.1mmol/L for 2 hours, this situation can also be diagnosed as diabetes. Therefore, the diagnosis of diabetes mainly relies on blood sugar judgment, whether there are symptoms is not the main, as long as the blood sugar reaches the standard, can be diagnosed as diabetes.