A Study to Evaluate the Pharmacodynamic, Efficacy and Safety of SHR-1703 in Asthma Patients With Eosinophil Phenotype

Inclusion Criteria: 1. Aged 18 to 75years (inclusive). 2. Weight ≥40 kg. 3. History of asthma≥ 1 year. 4. Documented treatment with Medium or high daily dose inhaled corticosteroid with additional controller medication within the 3 months prior to randomization. 5. Previously confirmed history of one or more asthma exacerbations within 1 year prior to randomization. 6. Blood eosinophils of ≥150 cells/µL at screening and baseline. 7. Pre-Bronchodilator FEV1% pred≥40% and\<80% at screening and baseline. 8. Asthma Control Questionnaire-6 score≥1.5. 9. Use highly effective contraceptive measures. 10. Willing to sign the informed consent form to participate in this study. Exclusion Criteria: 1. Subjects with Clinically significant pulmonary diseases； 2. Subjects with other diseases that could lead to elevated eosinophils； 3. Subjects with Immunodeficiency； 4. Poorly controlled hypertension; 5. Subjects with severe cerebrovascular disease; 6. Subjects with infection history requiring clinical intervention； 7. Subjects with parasitic infection； 8. Diagnosed Malignant tumor within 5 years prior to randomization; 9. Used non-selective β-blockers within 1 week prior to randomization; 10. Used either 5-lipoxygenase inhibitor or Phosphodiesterase-4 inhibitor within 1 week prior to randomization; 11. Blood donation or massive blood loss, or transfusion of blood products or immunoglobulins within 4 weeks prior to randomization; 12. Live attenuated vaccine inoculated within 4 weeks before randomization; 13. Allergen Immunotherapy within 8 weeks prior to randomization； 14. Used systemic immunosuppressants or immunomodulators, or biologics or Th2 cytokine inhibitors within 12 weeks prior to randomization or within 5 half-lives of the drug; 15. Bronchial thermoplasty within 1 year prior to randomization； 16. Subjects have planned Surgery or other medical procedures that may affect evaluation during the study period; 17. Subjects with significant laboratory abnormality at screening； 18. Subjects have prolonged QTc interval or other electrocardiogram abnormality with significant safety risk at screening; 19. Current smokers or ex-smokers who have given up smoking for \<6 months ，or positive smoke test, and/or have a smoking pack history of \> 10 pack years; 20. History of drug or substance abuse or alcohol abuse within 1 year prior to screening; 21. Subjects participated another clinical studies and received active drug within 30 days or 5 half-lives prior to screening; 22. Subjects is pregnant, lactating,or planning to become pregnant; 23. Subjects have a known history of hypersensitivity or intolerance to anti-IL-5 mabs or other biological agents; 24. Other conditions unsuitable for participation in the study per investigator judgement.