The difference between hyperglycemia and diabetes is that blood sugar is not defined by the same values. Hyperglycemia is not necessarily diabetes, but people with diabetes generally have hyperglycemia. The normal adult fasting blood glucose range is 3.9~6.1mmol/L, postprandial blood glucose should be less than 7.8mmol/L. When the fasting blood glucose is higher than the normal value of 6.1mmol/L and the postprandial blood glucose is higher than 7.8mmol/L it belongs to the range of hyperglycemia, and oral glucose tolerance test can be performed if necessary. If the 2-hour postprandial blood glucose is greater than or equal to 11.1mmol/L or fasting blood glucose is greater than or equal to 7.0mmol/L, accompanied by the three more and one less typical symptoms of diabetes, then the diagnosis of diabetes is considered. During trauma and surgery, body stress may lead to a transient elevation of blood glucose, which generally returns to normal when the stressor is removed. Diabetes mellitus is a chronic endocrine metabolic disease characterized primarily by hyperglycemia. Therefore, hyperglycemia does not necessarily belong to diabetes mellitus, but patients with diabetes mellitus generally belong to hyperglycemia. When abnormal blood glucose occurs, it is necessary to actively consult the doctor and follow the doctor’s instructions for reasonable treatment.