Primary Objective: To preliminarily evaluate the efficacy of the treatment regimen of HBM9161 680 mg administered subcutaneously weekly and sequentially every other week for 12 weeks in Chinese patients with active moderate to severe TED.

This is a multicenter, randomized, double-blind and placebo-controlled study. The investigational drug is HBM9161 injection, with the indication of TED. Subjects will be randomized to treatment group I, treatment group II, or placebo group. Subjects in treatment group 1 will receive HBM9161 680 mg subcutaneously once weekly (qw) for 12 doses; Subjects in treatment group 2 will receive HBM9161 680 mg subcutaneously once weekly (qw) for 6 doses, followed by HBM9161 680 mg subcutaneously once every two weeks (q2w) for 3 doses; Subjects in placebo group will receive placebo subcutaneously once weekly (qw) for 12 doses. After the 12-week dosing period, there will be a 5-week follow-up period.

Inclusion Criteria:

1. Signed written informed consent form.
2. Male or female between the ages of 18 and 70 (including boundary values).
3. Active TED associated with a clinical diagnosis of Graves' disease or Hashimoto's thyroiditis with CAS ≥ 3 at the screening visit and baseline (both on a 7-item scale) in the eye with the most severe proptosis.
4. The active period of TED starts within 9 months prior to screening visit
5. Positive anti-TSHR antibody at screening visit.
6. Subject is willing and able to receive treatment and complete corresponding assessments as required by the protocol.

Exclusion Criteria:

1. Other uncontrolled concurrent diseases
2. Serious TED requiring surgery or radiotherapy
3. Suffer from autoimmune diseases or ophthalmic conditions other than TED that, in the opinion of the investigator, would impact the assessment of the study drug
4. No significant laboratory abnormalities