1, whether the clinical symptoms of "three more and one less" typical manifestations, that is, eating more, drinking more, more frequent urination, but weight loss, the patient obviously feel fatigue;

2, monitoring the patient's fasting glucose, postprandial glucose, random glucose, if the fasting blood sugar More than 7.0mmol/L, postprandial blood glucose or random blood glucose more than 11.1mmol/L, combined with typical clinical symptoms can be diagnosed;

3. Diagnosis by glucose tolerance test. Patients fasting 8-10 hours after the test, if the fasting blood glucose more than 6.0mmol / L or more than 5.6mmol / L, two hours after the meal blood glucose more than 7.8mmol / L, combined with whether there is a family history of diabetes and obesity symptoms and so on to confirm the diagnosis.