1. Male or female, 18-70 age years, both inclusive;

2. BMI is 20.0 to 40.0 kg/m2, both inclusive;

3. Type 2 diabetes mellitus diagnosed for at least 3 months before the screening visit;

4. HbA1c 7.5-11.0% (both inclusive) by local laboratory analysis;

5. At screening:

1) Treatment with metformin alone on a stable dose (≥1500 mg or at the maximum tolerated dose [MTD, ≥1000 mg]) for ≥3 months, or 2) Treatment with metformin at the above dose level combined with a second OAD (AGI, SU, TZD, glinides, DPP-4i or SGLT2i) on a stable dose (≥half of the max approved dose according to local label, or at the MTD) for ≥3 months.

1. Use of systemic glucocorticoids within 3 months prior to the screening;

2. Use of weight loss drugs within 3 months prior to the screening.

3. Treatment with insulin within 1 year prior to screening (except for short-term or treatment for gestational diabetes);

4. Laboratory findings at the screening visit:

5. Personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN2)；

6. Cardiac disorder defined as: congestive heart failure (NYHA class III-IV), diagnosis of unstable angina pectoris, cerebral stroke and/or myocardial infarction within the last 6 months prior to screening and/or planned coronary, carotid or peripheral artery revascularization procedures;

7. Severe uncontrolled treated or untreated hypertension (systolic blood pressure ≥160 mmHg or diastolic blood pressure ≥100 mmHg);

8. Proliferative retinopathy, maculopathy, painful diabetic neuropathy, diabetic foot ulcer or intermittent claudication requiring acute treatment;

9. History of pancreatitis (acute or chronic);

10. Pregnancy, breast-feeding, intention of becoming pregnant during the trial; or women of childbearing potential (WOCBP) or male subject not using adequate contraceptive measures；