[Objective] To explore the association between methyltransferase-like 3 (METTL3) and prostate cancer (PCa) prognosis, so as to establish a novel prognostic prediction model for PCa. [Methods] Public datasets and PCa tissue microarray were used to evaluate the gene and protein expressions of METTL3, the association between METTL3 and Gleason score (GS), and the ability of METTL3 to predict poor outcomes of PCa.A nomogram was constructed to quantitatively evaluate the prognosis of PCa. [Results] The gene and protein expressions of METTL3 were significantly upregulated in PCa tissues compared to normal tissues (P<0.05). Moreover, the expressions of METTL3 were significantly higher in high-risk PCa tissues (GS>7) compared to low-moderate risk PCa tissues (GS≤7) (P<0.05). Patients with elevated expressions of METTL3 exhibited poorer short-term and long-term progression-free and overall survival outcomes when compared to those with lower expressions of METTL3 (P<0.05). In addition, a risk model composed of 7 target genes regulated by METTL3 N6-methyladenine (m6A) modification was established.The 7 target genes were closely associated with the cell cycle process.The protein expression of METTL3 exhibited a significant positive correlation with the protein expression of cell cycle protein B1 (CCNB1) (r=0.30, P=0.002 5). [Conclusion] METTL3 exhibits the potential as a prognostic predictor for PCa, which may affect PCa prognosis through the regulation of the expressions of target genes closely associated with the cell cycle process via m6A modification.