The purpose of the trial is to evaluate the effect of Chiglitazar added to metformin to type 2 diabetes Inadequately controlled with metformin Monotherapy.

This clinical trial is a multi-center, randomized, double-blind, placebo parallel control design, and uses superiority test to determine whether the experimental group is superior to the control group in terms of main efficacy endpoints.

Inclusion Criteria:

1. ) Provide a signed and dated informed consent form;
2. ) Men and women aged ≥ 18 years and ≤ 75 years;
3. ) According to the World Health Organization ( the WHO ) 1999 criteria for the diagnosis of type 2 diabetes;
4. ) After metformin stable dose monotherapy (≥1500 mg/day or maximum tolerated dose, but the maximum tolerated dose not < l000 mg/day) for at least 8 weeks;
5. ) The local HbA1c value during the screening period: 7.5% ≤ HbA1c ≤ 11% ;
6. ) The HbA1c value of the central laboratory before randomization: 7.0% ≤ HbA1c ≤ 10.5% ;
7. ) BMI ≥ 18.5 kg/m2 and ≤ 35 kg/m 2 ;
8. ) Fasting C- peptide ≥ 0.5 nmol/L ;
9. ) Women of Childbearing Potential ( WOCBP ) should take reliable contraceptive measures at least 1 month before the screening, during the entire trial, and within 3 months after completing the trial; male subjects should take reliable contraceptive measures to avoid making their sexual partners to pregnant during the entire trial and within 3 months after the trial.

Exclusion Criteria:

1. ) Type 1 diabetes;
2. ) Pregnancy or lactation;
3. ) The New York Heart Association (NYHA ) defines congestive heart failure as grade III or IV ;
4. ) Significant history of cardiovascular and cerebrovascular diseases within 6 months before screening, defined as myocardial infarction, coronary artery bypass graft or angioplasty, valvular disease or repair, unstable angina, transient brain Ischemic attack, or cerebrovascular accident;
5. ) Suffered from malignant tumors (except cured basal cell carcinoma) within 5 years before screening;
6. ) Edema of lower limbs or edema of the whole body;
7. ) Moderate to severe renal insufficiency [ Calculated eGFR<60 ml/ ( min*1.73m2 ) using CKD - EPI formula ];
8. ) urinary albumin-to-creatinine ratio of > 300 mg /g;
9. ) Triglyceride> 5.6 mmol /L;
10. ) Active liver disease and /or obvious liver function abnormalities, defined as AST>2.5 times the upper limit of normal value and/or ALT>2.5 times the upper limit of normal value and/or total bilirubin >1.5 times the normal value Upper limit
11. ) Clinically significant arrhythmias in the electrocardiogram examination and treatment or intervention are required. The investigator judges that it is not suitable to participate in this clinical trial;
12. ) Human immunodeficiency virus (HIV) antibody-positive; Treponema pallidum antibody positive; positive hepatitis B surface antigen and HBV DNA quantification values were higher than the upper; HCV antibodies and HCV RNA quantification values were higher than the upper ;
13. ) History of illegal drug abuse within 12 months before screening ;
14. ) Participated in other clinical trials within 90 days before screening ;
15. ) Donated whole blood, plasma, or platelets within 3 months before screening.
16. ) Before randomization, the investigator judged that the subjects had poor compliance with the study protocol or drug treatment, defined as the subjects taking less than 80% or more than 120% of the prescribed dose of chiglitazar/ placebo or metformin;
17. ) The investigator judged that it is not suitable to participate in this clinical trial.