To investigate the expression of FOXN2 in prostate cancer(PCa) tissues and its effects on the biology of PCa cells. Methods  Tissues were selected from 50 PCa patients and adjacent tissues who underwent surgery in our hospital. The expression levels of FOXN2 mRNA and protein in PCa tissue and adjacent tissues were detected by RT-qPCR experiment and Western-blot experiment, respectively, and the correlation between FOXN2 in PCa tissue and patients' clinicopathological characteristics was analyzed. The expression level of FOXN2 mRNA in normal prostate cells RWPE-1, PCa cells PC-3, DU145, and LNCaP was detected by RT-qPCR experiment. PC-3 cells as the research object were selected and divided into FOXN2 overexpression group, empty vector control group and control group. MTT experiment, flow cytometry experiment, Transwell experiment and Western blot experiment were used to detect cell proliferation, apoptosis, migration and invasion of each group and the expression of related proteins Bax, CyclinD1, and MMP-2.Results   Compared with the adjacent tissues, the mRNA and protein expression levels of FOXN2 were significantly decreased (P<0.05), which was consistent with the results in TCGA database.  Low FOXN2 expression was associated with lymphatic metastasis, TNM stage, and Gleason score in prostate cancer patients (P=0.003, 0.005, 0.002).  Compared with human normal prostate cells rwPE-1, FOXN2 showed low expression in PCa cells PC-3, DU145 and LNCaP (P<0.05), and PC-3 cells had the lowest expression.  Compared with the control group and the empty vector control group, the proliferation ability of PC-3 cells in FOXN2 overexpression group was significantly decreased (F=290.400, 57.735, 113.014, P<0.05) after treatment for 24, 48 and 72 h, and the expression level of CyclinD1 protein was significantly decreased (P<0.05).  The apoptosis rate and Bax protein expression level of PC-3 cells were significantly increased (P<0.05).  The migration and invasion ability of PC-3 cells were significantly decreased (P<0.05), and the expression level of MMP-2 protein was significantly decreased (P<0.05).Conclusions  FOXN2 is underexpressed in PCa tissues and cells, and overexpression of FOXN2 can inhibit the proliferation, migration and invasion of PCa cells, and promote cell apoptosis.