The purpose of this study is to conduct a multicenter prospective randomized controlled clinical trial, evaluating the effects of "therapeutic monitoring" on blood glucose control in type 2 diabetes.

In our study, about 480 type 2 diabetes patients will be enrolled from multiple centers in China. All participants will be randomly assigned into either the intervention group or the control group. All patients will be given basic diet, lifestyle instruction according to guidelines from home and abroad. The intervention group will be instructed to adjust the diet according to the ambulatory glucose profile (AGP) and the recorde log monitored by the continuous glucose monitoring system, thereby implementing "therapeutic monitoring". All patients will maintain the drug treatment unchanged and make the glucose level as far as possible within the target range (>3.9 and ≤10mmol/L), and record the amount of various food, then maintain the dietary pattern and the amount unchanged until the end of the study.

The primary objective is to evaluate the effects of "therapeutic monitoring" on blood glucose control in type 2 diabetes, as measured by change in HbA1c level from baseline to 12-week follow-up in both intervention group and control group.

THe secondary endpoint are 1) 1)Difference in TIR (time in range, time in target glucose range, 3.9-10.0mmol/L) at 12 weeks in both groups. 2)Fasting plasma glucose (FPG), lipids and other metabolic related components and parameters such as BMI will be measured. 3)Using questionnaires to evaluate the patients' satisfaction with Flash Glucose Monitoring System.

Inclusion Criteria:

• Type 2 diabetes defined as WHO(1999) diagnostic criteria;
• HbA1c ≥ 7% and ≤ 9% at screening; and fasting plasma glucose ≥ 7.0mmol/L, and <13.3mmol/L;
• Duration: 3 months~15 years;
• BMI: 24~ 28 kg/m2;
• Using 1-3 oral medications when enrolled, and the treatment pattern was stable for at least 3 months and can maintain during this study period;
• Sign the informed consent. Details please see the study protocol.

Exclusion Criteria:

• There are serious diabetic complications, heart, brain, liver and kidney diseases, allergic diseases and organic diseases;
• The subject is currently pregnant, intends to become pregnant or is unwilling or unable to contraception during the study (female only);
• The subject has symptoms or signs of skin lesions, scab, redness, infection or edema at the sensor application site that may affect the accuracy of sensor application or interstitial glucose measurements;
• The subject has a concomitant disease and the investigator believes it will affect the study or pose a risk to the safety or benefit of the subject or research worker.
• An X-ray, MRI, or CT examination is scheduled during the study period, and the appointment could not be changed to before the study started or after the study ended;
• Take aspirin > 200 mg / day, and the drug may be added during the entire study period; Details please see the study protocol.