This study is a prospective, single-arm, open-label, dose-escalation study. A total of 5 dose groups were pre-defined in this study. The drug was administered once every 6 weeks.The drug would be administered for 1 to 4 cycles. After each dose group completed the enrollment and DLT observation, based on the participant's safety tolerance, radiation dosimetry, and preliminary efficacy evaluation results, it was decided whether to adjust the dose of the subsequent dose groups or to suspend the dose escalation.

Inclusion Criteria:

1. Aged >=18 years old.
2. Patients with metastatic castration-resistant prostate cancer who have failed standard treatments.
3. According to RECIST 1.1, there is at least one measurable lesion.
4. ECOG performance status 0-1.
5. Laboratory examination should meet: ① Blood routine: hemoglobin (HGB) ≥90g/L, neutrophil count (ANC) ≥1.5×10^9/L, platelet count ( PLT) ≥100×10^9/L; ②Blood biochemistry: total bilirubin (TBIL) ≤1.5×upper limit of normal (ULN), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3.0×ULN, serum creatinine ( Cr)≤1.5×ULN or calculate the creatinine clearance ≥50 mL/min according to the Cockcroft-Gault formula method.

Exclusion Criteria:

1. Received anti-tumor therapy within 4 weeks before enrollment.
2. Participated in other clinical trials within 4 weeks before enrollment and used clinical investigational drugs during this period.
3. Have undergone surgery within 4 weeks before enrollment.
4. Not recovered from the adverse reactions caused by previous anti-tumor treatments (≥CTCAE grade 1).
5. Central nervous system metastases with clinical symptoms.
6. With any situations that the researcher considers inappropriate to participate in this research.