Glargine is commonly used in insulin supplemental therapy in patients with type 2 diabetes(T2D) at present. However, many patients who treated with glargine still have poor blood glucose control because of insufficient insulin dose or improper oral medication. This study aims to investigate the optimal treatment scheme in order to improve the blood control in these patients. Continuous Glucose Monitoring System (CGMS) will be used to assess the blood glucose control at baseline and the moment when the patients achieved standard. Oral medications will be standardized first, and insulin doses will be adjusted according to blood glucose values obtained by self-monitoring. Glycemic control will be considered as reaching target of glucose if the fasting capillary blood glucose is less than 6.1 mmol/L. The maximum period of blood glucose adjustment will be 1 months. Oral medication, the type and dosage of insulin, exercise status, insulin injection skill evaluation, islet function, duration of diabetes, complications and insulin antibodies will be recorded in detail at baseline, reaching target of glucose standard and 3 months after reaching target of glucose.

Inclusion Criteria:

1. Patients with T2DM, which was defined bypublished Criteria of World Health Organization in 1999;
2. Patients were using glargine with or without oral hypoglycemic drugs and having a stable dose of glargine for more than 2 month would be recruited into this study;
3. Patients had relatively constant diet and exercise in 2 month before the study.
4. Fasting blood glucose was between 6.1 and 16mmolL, and postprandial (or random) blood glucose <22.2mmol/L

Exclusion Criteria:

1. Patients with severe cardiovascular diseases, such as stroke, transient ischemic attack, myocardial infarction, unstable angina, coronary artery bypass grafting, percutaneous coronary intervention, and heart failure;
2. Patients with severe infectious diseases;
3. Patients with acute complications of diabetes on admission, such as diabetic ketoacidosis, diabetic hyperosmolar nonketotic coma, and lactic acidosis;
4. Patients with history of psychiatric disorders and were unsuitable to use CGMS;
5. Any other situations that made patients unsuitable to participate in the study, such as alcoholism and drug abuse.