Allergic rhinitis (AR) is a non-infectious chronic inflammatory disease of the nasal mucosa mainly mediated by immunoglobulin E after exposure to allergens in atopic individuals. The typical symptoms of AR are paroxysmal sneezing, watery rhinorrhea, itching, and nasal congestion, which may be accompanied by ocular symptoms, including eye itching, tearing, redness, and burning sensation, which are more common in patients with hay fever allergies.

Main Inclusion Criteria:

1. Voluntarily sign the informed consent form.
2. Seasonal allergic rhinitis has been prevalent for at least 2 years.Positive for allergens associated with seasonal allergic rhinitis.
3. Poor control of seasonal allergic rhinitis with nasal glucocorticoids or other therapeutic agents during the same pollen season in the past.
4. Weight≥30kg.
5. Symptom severity scores for the season met the enrollment criteria.

Main Exclusion Criteria:

1. Other nasal comorbidities or co-morbidities/states that may be present at the time of screening that affect efficacy determination.
2. Subjects whose allergen exposures in their home or work environments may be expected to change significantly during the trial period.
3. Subjects with poorly controlled recent asthma conditions.
4. Presence of current or past history of infection of special concern, e.g., active tuberculosis, helminthic infections, severe herpes virus infections, etc.
5. Previous use of anti-interleukin 4 receptor alpha subunit (IL4Rα) monoclonal antibody.
6. Have a serious underlying medical condition that, in the opinion of the investigator, may pose a risk to subject safety by participation in a clinical trial.

Part one subjects received open-label treatment. Part two subjects received double-blind treatment.