Prostate cancer (PCa) is a frequently occurring malignant tumor affecting male reproductive system. miR-374a-5p was identified to participate in regulation of several tumors. The aim of the research was to discuss the influence for miR-374a-5p upon PCa progression and prognosis. A total of 112 PCa and 110 benign prostatic hyperplasia tissue samples were collected for the study. Real-time quantitative polymerase chain reaction was adopted to examine miR-374a-5p level in PCa tissues and cells. Kaplan-Meier and Cox model were applied to evaluate prognostic significance of miR-374a-5p for PCa. CCK8 and Transwell assays were carried out to analyze the efficacy of miR-374a-5p in PCa cell proliferation, migration and invasion. miR-374a-5p was under-expressed in PCa tissues and cells. Low expression of miR-374a-5p is linked to less favorable prognosis in PCa sufferers. Additionally, Cox analysis revealed that miR-374a-5p and TNM stage were two independent prognostic factors for PCa. Cellular assays showed that upregulating miR-374a-5p suppressed PCa cell proliferation, migration, and invasion. Conversely, knockdown of miR-374a-5p facilitated PCa cell proliferation, migration, and invasion. miR-374a-5p expression decreased in PCa and was remarkably related to poor prognosis in PCa patients. miR-374a-5p acts in PCa by inhibiting cell proliferation, migration, and invasion. Consequently, miR-374a-5p has potential to act as a prognostic biomarker and a target for clinical therapeutic intervention in PCa.