Prostate adenocarcinoma (PRAD) is a major threat to male health worldwide with a high mortality rate. New therapeutic strategies for the treatment of this malignant disease are of tremendous significance. Much attention has been paid to the involvement of immune cells in the prevention and treatment of cancer as well as how their regulatory systems contribute to effective cancer treatment. In this study, we constructed prognostic immune profiles based on The Cancer Genome Atlas (TCGA)-PRAD data sets and tested their predictive power on total and internal data sets. Then, we looked at how the lymphocyte of tumor invasion varied between the high-risk group and the lowrisk group. Five immune-related genes made up the immune marker, which was an independent predictive factor in patients with PRAD. Patients in the low-risk score group had a higher rate of overall survival and a stronger infiltration of immune cells in the tumor microenvironment, which was highly related to clinical outcomes but required prospective validation.