Purpose: Although the combination of androgen deprivation therapy with docetaxel or abiraterone acetate and prednisone has become a standard treatment for metastatic hormone-sensitive prostate cancer (mHSPC) and has shown improved overall survival, a subset of patients still progress to castration-resistant disease. However, the underlying molecular features in these patients remain poorly understood. Materials and Methods: We performed single-cell RNA sequencing (scRNA-seq) on 12 tissue samples, including 2 mHSPC samples, 7 primary prostate cancer (PCa) samples, and 3 matched normal samples from 7 patients. Raw sequencing data was processed by Cell Ranger software (10X Genomics) and aligned to the human reference genome (GRCh38). A comprehensive analysis of samples from patients with mHSPC was also conducted and validated using a cohort of 52 patients with mHSPC. Results: Our results identified distinct subpopulations within luminal and mononuclear phagocyte (MNP) clusters characterized by proliferative activation associated with unfavorable clinical outcomes. Furthermore, we observed that the MNP cluster exhibited significant proliferation activity. To understand the underlying mechanisms associated with aggressiveness, we conducted cell-cell interaction, copy number variation and pseudotime analysis. Utilizing 87 network genes from scRNA-seq, we classified 52 mHSPC patients into 2 molecular subtypes and demonstrated their correlation with distinct transcriptomic profiles and survival outcomes. Importantly, a 14-gene signature derived from 3 distinct gene sets exhibited a strong association with patient survival and drug response. The prognostic value of our findings was further validated in large-scale cohorts comprising localized PCa, metastatic PCa, mHSPC, and metastatic castration-resistant PCa patients. Conclusion This study provides valuable insights into the identification of high-risk patients, novel biomarkers, and potential therapeutic targets for individuals with mHSPC. Furthermore, the results in this study can serve as a basis for future investigations aimed at refining prognostic strategies and developing targeted therapies for patients with mHSPC.