Abstract: Selenium is an essential trace element for humans and it has three common forms: Inorganic selenium, organic selenium, and nano-selenium. Among them, selenium nanoparticles (SeNPs) have attracted extensive attention because of its low toxicity and high bioactivity. Peptide-SeNPs (P-SeNPs) are prepared by using bioactive peptides as surface stabilizers. Owing to the synergistic effect of selenium and peptides, P-SeNPs have superior stability and enhanced bioactivity; thus, their investigation is highly significant. This article systematically reviews the preparation methods and biological activities of P-SeNPs, elaborates on the physical, chemical, and biological preparation methods, and examines the underlying mechanisms of P-SeNPs bioactivities, including antioxidant, antitumor, immunomodulatory, and antibacterial effects. The aim is to provide theoretical references for further studies on P-SeNPs and their potential applications in the food industry.