Prostate cancer is a prevalent cancer in elderly men, and immunotherapy has emerged as a promising treatment approach in recent years. The aim of immunotherapy is to stimulate the body’s immune system to target and destroy cancer cells. Cancer vaccines that are highly specific, safe, and capable of creating long-lasting immune responses are a key focus in cancer immunotherapy research. Despite progress in clinical trials showing positive results, the practical use of cancer vaccines still encounters various obstacles. The complexity of the immune microenvironment and variations in the immune systems of individual patients have hindered the progress of research on prostate cancer vaccines. This review examines the history and mechanisms of cancer vaccines, summarizes recent clinical research findings, and explores future directions in the development of prostate cancer vaccines.