Recent research has increasingly suggested an association between changes in specific blood metabolites and prostate cancer (PCa) development. However, it remains unclear whether these observed associations represent a causal relationship. To reveal the potential causal associations between blood metabolites and PCa risk, we conducted a comprehensive two-sample Mendelian randomization (MR) analysis. We used genetic instruments for 514 and 490 metabolites from two independent comprehensive genome-wide association studies. These studies included 14,295 individuals of European ancestry from the INTERVAL/EPIC-Norfolk cohorts and 8299 individuals of European ancestry from the Canadian Longitudinal Study on Aging cohort. Summary statistics of PCa risk involving 122,188 cases and 604,640 controls of European ancestry individuals were analyzed. The associations between metabolites and PCa risk were evaluated using the inverse-variance weighted method, supplemented by sensitivity analyses including MR-Egger and MR-PRESSO tests. Additionally, we conducted a phenome-wide MR analysis to assess the potential side effects of targeting the identified metabolites for PCa intervention. Our analysis revealed 107 unique blood metabolites significantly associated with PCa risk, with 43 of these associations consistently replicated using instruments from two independent data sets. This study provides novel insights into the potential role of specific metabolites in the etiology of PCa, which warrants further investigations.