Abstract: Lutetium-177 (¹⁷⁷Lu)-prostate specific membrane antigen (PSMA)-617 is a small-molecule radioligand therapy (RLT) drug targeting PSMA. By selectively delivering the β-emitting radionuclide ¹⁷⁷Lu to PSMA-expressing prostate cancer cells, it induces tumor cell death. The agent has been approved in multiple nations and regions for the treatment of PSMA-positive metastatic castration-resistant prostate cancer, thereby expanding therapeutic options for this patient population. This review outlines the development, pharmacological properties, and current clinical applications of ¹⁷⁷Lu-PSMA-617, aiming to provide a theoretical basis for the clinical practice of RLT in prostate cancer treatment.