The goal of this clinical trial is to assess the safety, tolerability, pharmacokinetics, pharmacodynamics and immunogenicity of 9MW3011 in Chinese patients with Polycythemia Vera（PV）.

The multiple dose fo the starting dose cohorts will comprise 3 dose cohorts of 8 PV subjects each.In each cohort, subjects will receive 9MW3011 via intravenous infusion.A decision on whether to proceed with case expansion and dose escalation will be based on the safety and PK-PD data.

Inclusion Criteria:

1. Male and female patients aged 18 years or older at the time of screening.
2. A confirmed diagnosis of PV according to the revised 2016 World Health Organization criteria and are resistant to or intolerant of hydroxyurea or Interferon alpha.
3. Have a treatment history for PV with resistance or intolerance to hydroxyurea or Interferon alpha.
4. Subjects receiving hydroxyurea, Interferon alpha, or ruxolitinib must complete a washout period before administration of the investigational drug.
5. Must agree to adhere to appropriate contraception requirements during the study period.
6. All female subjects with fertility capacity tested negative for blood pregnancy.
7. Voluntarily participate in clinical trials and agrees to participate in the study by giving written informed consent.

Exclusion Criteria:

1. The spleen is palpable at least 5 centimeters below the left costal margin upon palpation at baseline.
2. Heart failure, unstable angina pectoris, myocardial infarction, and other thrombotic diseases within the 6 months prior to screening.
3. Abnormal QTc interval of electrocardiogram within the 6 months prior to screening.
4. Uncontrolled hypertension prior to screening.
5. Any non-PV myeloproliferative neoplasms (MPN).
6. Blast cells and blast granulocytes in the peripheral blood within the 3 months prior to screening.
7. Hematological indicators do not meet the requirements at the time of screening.
8. Known positive for active hepatitis B, hepatitis C, syphilis or human immunodeficiency virus (HIV) infection.
9. History of invasive malignancies within the last 5 years.
10. Severe infection or uncontrolled active infection.
11. Other hematological and lymphatic system diseases or any diseases causing hemolysis or erythrocyte instability.
12. Other systemic diseases or a family history of systemic diseases, may affect the subject's safety or any other diseases and physiological conditions that may affect the results of the study, judged by the investigator.
13. Specific history of allergies.
14. Subjects who have used monoclonal antibodies within the 6 months prior to screening.
15. Patients who have received vaccinations within 6 weeks prior to screening.
16. Subjects who have received other antitumor therapeutic drugs for PV prior to screening.
17. Chronic diseases requiring treatment with systemic glucocorticoids or other immunosuppressants.
18. History of drug abuse or illicit drug use within 3 months prior to screening.
19. Participation in other clinical trials within 3 months prior to screening.
20. Planned elective surgery during the study.
21. History of surgery within 3 months prior to screening.
22. Intolerable iron deficiency-related symptoms judged by the investigator prior to the first dosing.
23. Pregnant or lactating females; women of reproductive age who are not using effective contraception.
24. Individuals directly associated with the research and/or their immediate family members.
25. Other factors which may potentially affect the assessment of the study results by the investigator.