1. Pre-meal glucose monitoring: for patients injecting basal, mealtime or premixed insulin. Fasting blood glucose levels should be the first concern when blood glucose levels are high. Pre-meal blood glucose should also be measured when there is a risk of hypoglycemia with other glucose-lowering treatments (those treated with insulinotropic agents and with good glycemic control). Post-meal blood glucose monitoring: It is applicable to patients who inject meal-time insulin and those who use dietary control and exercise to control blood glucose. In the fasting blood glucose and preprandial blood glucose has been well controlled but HbA1c still can not meet the standard can be tested by postprandial blood glucose to guide the treatment of postprandial hyperglycemia. 3.Bedtime blood glucose monitoring: applicable to patients who inject insulin, especially those who inject insulin before dinner. 4.Nighttime blood glucose monitoring: used to know whether there is nighttime hypoglycemia, especially when there is unexplained fasting hyperglycemia, nighttime blood glucose should be monitored. 5.Blood glucose should be monitored in time when hypoglycemia symptoms appear or when hypoglycemia is suspected. 6. Blood glucose should be monitored before and after strenuous exercise.