To evaluate the efficacy and dose-response relationship of HRS9531 injection versus placebo in controlling blood glucose after 20 weeks of treatment in subjects with type 2 diabetes who have suboptimal glycaemic control after conventional lifestyle or metformin intervention.

Inclusion Criteria:

1. Male or female subjects ,18-65 years of age, agreed and signed the informed consent
2. Type 2 diabetes mellitus diagnosed for at least 6 months before the screening visit.
3. Treated with conventional lifestyle intervention and stable treatment with metformin (≥1000 mg/day) at least 8 weeks prior to screening.
4. HbA1c 7.5-10.5% (both inclusive) at screening visit.

Exclusion Criteria:

1. Presence of any clinically significant results in examination at screening visit.
2. Uncontrollable hypertension.
3. A history of type 1 diabetes, specific diabetes, or secondary diabetes.
4. Acute diabetic complications or severe hypoglycemia events within 12 months prior to screening.
5. History of acute cardiovascular and cerebrovascular diseases within 6 months prior to screening.
6. Any organ-system malignancies developed within 5 years except for cured local basal cell carcinoma of the skin and carcinoma in situ of the cervix.
7. Present or suspected depression, bipolar disorder, suicidal tendencies, schizophrenia, or other more serious mental illness.
8. Surgery is planned during the trial.
9. Mentally incapacitated or speech-impaired.
10. Pregnant or lactating woman.
11. In the investigator's judgment, there were circumstances that affected subject safety or otherwise interfered with the evaluation of results.