This study will first conduct a phase II clinical study, and on the basis of the phase II clinical study, subsequent clinical research will be carried out.

Inclusion Criteria:

1. Voluntarily join this study and sign the informed consent form;
2. Age ≥ 18 years;
3. Expected survival time ≥ 3 months;
4. Unresectable metastatic castration-resistant prostate cancer;
5. Meet the definition of mCRPC according to PCWG3 criteria;
6. Agree to provide archived tumor tissue specimens from primary or metastatic lesions within 3 years or fresh tissue samples;
7. Meet the evaluable lesion requirement defined by any one of the following assessment criteria;
8. ECOG performance status score of 0 or 1;
9. Toxicities from prior anti-tumor therapy have recovered to ≤ Grade 1 as defined by NCI-CTCAE v6.0;
10. No severe cardiac dysfunction, with left ventricular ejection fraction ≥ 50%;
11. Organ function levels must meet the required criteria;
12. Urine protein ≤ 1+ or < 1000 mg/24h;
13. All enrolled patients must use adequate barrier contraceptive measures throughout the entire treatment period and for 7 months after the end of treatment.

Exclusion Criteria:

1. Patients with metastatic castration-resistant prostate cancer who are suitable for radical local therapy;
2. Patients with non-prostatic acinar adenocarcinoma confirmed by histopathology or cytology, among others;
3. Patients who have previously received antibody-drug conjugates using topoisomerase I inhibitors as the toxin, among others;
4. Use of chemotherapy, targeted therapy, biological therapy, etc., within 4 weeks or 5 half-lives prior to study randomization;
5. History of severe heart disease or cerebrovascular disease;
6. Long-term systemic corticosteroid therapy with prednisone >10 mg/day ongoing before the first dose, among others;
7. Active autoimmune diseases and inflammatory diseases;
8. Any thrombotic event within 6 months prior to randomization;
9. Prolonged QTc interval, complete left bundle branch block, etc.;
10. Diagnosis of active malignant tumors within 3 years prior to study randomization;
11. Hypertension inadequately controlled by two antihypertensive medications;
12. Patients with poorly controlled blood glucose;
13. History of ILD requiring steroid therapy, or current ILD, or grade ≥2 radiation pneumonitis;
14. Concurrent pulmonary diseases resulting in clinically severe respiratory function impairment;
15. Patients with active central nervous system metastases;
16. Severe infection occurring within 4 weeks prior to study randomization, etc.;
17. Presence of large serous cavity effusion, or serous cavity effusion with symptoms, etc.;
18. Imaging findings indicating tumor invasion or encasement of the abdomen, chest, etc.;
19. Severe non-healing wounds, ulcers, or fractures within 4 weeks prior to signing informed consent;
20. Trial participants with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to signing informed consent;
21. Patients with inflammatory bowel disease, history of extensive bowel resection, history of immune-related enteritis, intestinal obstruction, or chronic diarrhea, etc.;
22. Patients with a history of allergy to recombinant humanized antibodies or allergy to the investigational drug;
23. History of autologous or allogeneic stem cell transplantation;
24. Positive for human immunodeficiency virus antibodies, active hepatitis B virus infection, or hepatitis C virus infection;
25. History of severe neurological or psychiatric disorders;
26. Receipt of other unapproved clinical investigational drugs or treatments within 4 weeks prior to study randomization;
27. Trial participants planning to receive vaccination or having received live vaccines within 28 days prior to study randomization;
28. Other conditions deemed by the investigator as unsuitable for participation in this clinical trial due to complications or other circumstances.