Background: Abnormal regulation of the NOTCH signaling pathway in prostate cancer (PCa) can promote tumorigenesis, progression, and T cell exhaustion. However, there has not been a comprehensive analysis of NOTCH family genes (NOTCHs) as potential therapeutic targets and prognostic biomarkers for PCa patients. Methods: NOTCHs expressions in various types of cancer tissues and normal adjacent tissues in the TIMER and UALCAN database were screened. Immunohistochemistry (IHC) and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) were applied to validate the expression pattern of NOTCHs in clinical samples. The relationships of NOTCHs expression and clinicopathologic parameters or disease-free survival (DFS) were evaluated via GEPIA2 and UALCAN. A proteins network was built using STRING and GeneMANIA. Additionally, NOTCHs mutation status was analyzed by cBioportal. Finally, we used GDSC and TIMER to investigate NOTCH signaling-related drugs and immune cell infiltration. Results: The transcriptional levels of NOTCH1 and NOTCH4 in PCa tissues were significantly lower than in normal tissues, which was further validated in clinical patients' tissue samples. Furthermore, NOTCH1, NOTCH3, and NOTCH4 expressions in PCa were associated with worse DFS. Interestingly, there was a significant positive correlation between NOTCHs and androgen receptor (AR), but not with AR-related genes (KLK3 and TMPRSS2). Finally, we found that NOTCHs expressions were remarkably associated with infiltration of B cells, CD8(+)/CD4(+) T cells, macrophages, neutrophils, and dendritic cells, which indicated that NOTCHs mutation status might be a potential therapeutic target for -tinib antineoplastic drugs. Conclusions: The expression and mutation of NOTCH 1-4 in PCa were associated with disease progression, prognosis, immune cell infiltration, and drug sensitivity.