Inclusion Criteria:

• Age ≥ 18 years.
• Voluntary signed informed consent.
• Confirmed diagnosis of diffuse toxic goiter (Graves' disease).
• Abnormal thyroid function tests (e.g., elevated T4, and suppressed TSH).
• No prior or recent use of antithyroid medications (discontinued for at least 4 weeks).
• Female participants must be postmenopausal, surgically sterile, or using a highly effective method of contraception.
• Male participants must agree to practice abstinence, use a highly effective method of contraception， or have undergone vasectomy.
• Ability to comply with the follow-up schedule and understand and adhere to the study requirements.

Exclusion Criteria:

• Non-diffuse toxic goiter-induced hyperthyroidism.
• Previous radioactive iodine treatment or thyroid surgery.
• History or risk of thyroid storm.
• Use of thyroid hormone medications within the past 6 weeks.
• accompanied by active thyroid eye disease.
• Thyroid eye disease treated with radiation/surgery,or need for urgent surgery surgical or medical intervention.
• Optic nerve lesions or corneal damage.
• Use of steroids or immunosuppressants within the past 3 months,or those who have used biologics within 6 months
• Inability to quit smoking during the study.
• Allergy to the study drug or monoclonal antibodies.
• Participation in another clinical trial within the past 3 months.
• Abnormal electrocardiogram.
• Significant hepatic or renal dysfunction.
• Pregnancy,breastfeeding,or positive pregnancy test.
• Positive for HIV,syphilis,hepatitis B,or hepatitis C.
• History of drug or substance abuse.
• Other autoimmune diseases requiring treatment.
• History of malignant tumors.
• Splenectomy or major surgery within the past 6 months.
• Severe cardiovascular,pulmonary,hepatic,renal,neurological,or hematological diseases.
• Other conditions deemed unsuitable by investigators.