The main purpose of this study is to assess the safety and tolerability of multiple subcutaneous injections of HRS9531 in patients with type 2 diabetes mellitus who have suboptimal glycaemic control after conventional lifestyle or metformin intervention.

Inclusion Criteria:

1. Males and infertility females, 18-65 years of age, inclusive, on the date of signing informed consent.
2. Diagnosed with type 2 diabetes mellitus (T2DM) for at least 6 months.
3. Treated with conventional lifestyle intervention alone or stable treatment with metformin (≥1000 mg/day) at least 8 weeks prior to screening.
4. 7.0% ≤ HbA1c ≤10.5% at screening.

Exclusion Criteria:

1. History or presence of vital organ primary diseases, including but not limited to neuropsychiatric, cardiovascular, digestive, respiratory, urinary, endocrine, blood, immune and other diseases, judged by researchers to be unsuitable for this study.
2. Diagnosed or suspected with type 1 diabetes mellitus, special types of diabetes or secondary diabetes.
3. Have a history of acute complications of diabetes (diabetic ketoacidosis, lactic acidosis, hyperglycaemic hyperosmolar state, etc.) or episode of severe hypoglycaemic events within 12 months prior to screening.
4. Have a presence of proliferative diabetic retinopathy, diabetic macular edema, or nonproliferative diabetic retinopathy requiring treatment during the trial;
5. Participants in clinical trials of any drug or medical device in the 3 months prior to screening.
6. Breast-feeding women.
7. The investigator considers that the subject has any other factors that would make it inappropriate to participate in this study.