A Multi-centered，Randomized，Double-blind，Placebo-controlled Study to Evaluate the Efficacy and Safety of SHR-1703 in Eosinophilic Asthma

Inclusion Criteria: 1. At least 12 years of age 2. A minimum weight of 40kg 3. A medical history of at least 1 year that meets the diagnosis of asthma; 4. Current treatment with medium- or high- doses of ICS for at least 6 months and using steadily at least 3 months 5. Current treatment with an additional controller medication, besides ICS, for at least 3 months and using steadily at least 1 month 6. Absolute count of blood eosinophils suggests eosinophilic asthma 7. During the screening period and baseline, pre- BD FEV1% \< 80% 8. During the screening period and baseline, ACQ-6 score indicates asthma poor control 9. History of severe asthma exacerbation within the past 12 months prior to screening 10. Good compliance with eDiary completion 11. Take efficient contraceptive measures 12. Voluntarily sign the informed consent form to participate in this study Exclusion Criteria: 1. With other condition that could lead to elevated eosinophils 2. With Clinically significant pulmonary diseases 3. With existing immunodeficiency disease 4. With other clinically significant diseases that may affect lung function 5. With uncontrolled severe cardiovascular and cerebrovascular diseases 6. With uncontrolled hypertension and/or diabetes 7. With exacerbation, allergic rhinitis or sinusitis attacks, or clinical significant infection requiring intervention during 4 weeks prior to randomization 8. Recent major surgeries or surgical plans during the study period, or treatment measures that investigators believe may affect subject evaluation 9. Existing parasitic infections 10. Diagnosed as malignant tumor within the first 5 years of randomization 11. Significant abnormalities in screening period or baseline laboratory tests 12. Screening period or baseline ECG QTc prolongation 13. Prohibited drugs using during the pre randomization period 14. Participated in other clinical trials within 30 days prior to screening and used research drugs containing active ingredients, or was still within 5 half lives of the research drug at the time of screening 15. Smoking or quitting smoking for less than 6 months during screening, or previous smoking history ≥ 10 pack years 16. History of drug use, alcoholism, or substance abuse within the past year prior to screening 17. Allergic or intolerant to IL-5 monoclonal antibodies or other biological agents 18. Pregnant or lactating subjects 19. Other reasons why the researcher deemed it unsuitable for conducting this experiment