Antimicrobial peptides (AMPs) are small peptides found in nature and are crucial components of the innate immune system of various organisms. They exhibit broad inhibitory effects against bacteria, fungi, parasites, and viruses. The rise of antibiotic-resistant microorganisms and concerns about antibiotic use have driven the development of AMPs, which show promising applications in medicine, food, agriculture, and aquaculture. This review provides a comprehensive overview of AMP research, covering classification, mechanisms of action, design methods, environmental factors, application status, and future prospects in various fields. It also discusses the research progress on antiviral peptides, particularly those targeting the coronavirus (SARS-CoV-2). AMPs are classified based on their source, activity, structural characteristics, and amino acid-rich species. They are found in mammals, amphibians, microorganisms, and insects. Mammalian AMPs include cathelicidins and defensins, while amphibian AMPs are important for protecting against pathogens. Insect-derived AMPs are synthesized in fat bodies and blood cells, and microorganism-derived AMPs include peptides like nisin and gramicidin. Plant-derived AMPs are also present, with some showing antifungal activity. AMPs are categorized by their activity into antibacterial, antifungal, antiviral, antiparasitic, anti-HIV, and anticancer peptides. Antiviral peptides, especially those targeting the coronavirus, have been extensively studied due to the global pandemic. These peptides inhibit viral entry by targeting viral proteins and can be effective against various viruses, including SARS-CoV-2. Antiparasitic peptides target parasites like Leishmania and Trichomonas, while anticancer peptides can kill cancer cells through various mechanisms. AMPs are also classified based on their amino acid-rich species, such as proline-rich, tryptophan- and arginine-rich, histidine-rich, and glycine-rich peptides. Their structures include linear α-helical, β-sheet, and hybrid peptides. The mechanisms of AMP action include membrane targeting, which can involve pore formation, and non-membrane targeting, such as inhibiting protein biosynthesis, nucleic acid biosynthesis, protease activity, and cell division. Design methods for AMPs include site-directed mutation, de novo design, template-based design, self-assembly, chemical modification, cyclization, capping, conjugation, and synthetic mimics. These methods aim to enhance the stability, activity, and specificity of AMPs while reducing cytotoxicity. The review highlights the importance of AMPs in combating antibiotic resistance and their potential in various applications, emphasizing the need for further research to optimize their properties and applications.Antimicrobial peptides (AMPs) are small peptides found in nature and are crucial components of the innate immune system of various organisms. They exhibit broad inhibitory effects against bacteria, fungi, parasites, and viruses. The rise of antibiotic-resistant microorganisms and concerns about antibiotic use have driven the development of AMPs, which show promising applications in medicine, food, agriculture, and aquaculture. This review provides a comprehensive overview of AMP research, covering classification, mechanisms of action, design methods, environmental factors, application status, and future prospects in various fields. It also discusses the research progress on antiviral peptides, particularly those targeting the coronavirus (SARS-CoV-2). AMPs are classified based on their source, activity, structural characteristics, and amino acid-rich species. They are found in mammals, amphibians, microorganisms, and insects. Mammalian AMPs include cathelicidins and defensins, while amphibian AMPs are important for protecting against pathogens. Insect-derived AMPs are synthesized in fat bodies and blood cells, and microorganism-derived AMPs include peptides like nisin and gramicidin. Plant-derived AMPs are also present, with some showing antifungal activity. AMPs are categorized by their activity into antibacterial, antifungal, antiviral, antiparasitic, anti-HIV, and anticancer peptides. Antiviral peptides, especially those targeting the coronavirus, have been extensively studied due to the global pandemic. These peptides inhibit viral entry by targeting viral proteins and can be effective against various viruses, including SARS-CoV-2. Antiparasitic peptides target parasites like Leishmania and Trichomonas, while anticancer peptides can kill cancer cells through various mechanisms. AMPs are also classified based on their amino acid-rich species, such as proline-rich, tryptophan- and arginine-rich, histidine-rich, and glycine-rich peptides. Their structures include linear α-helical, β-sheet, and hybrid peptides. The mechanisms of AMP action include membrane targeting, which can involve pore formation, and non-membrane targeting, such as inhibiting protein biosynthesis, nucleic acid biosynthesis, protease activity, and cell division. Design methods for AMPs include site-directed mutation, de novo design, template-based design, self-assembly, chemical modification, cyclization, capping, conjugation, and synthetic mimics. These methods aim to enhance the stability, activity, and specificity of AMPs while reducing cytotoxicity. The review highlights the importance of AMPs in combating antibiotic resistance and their potential in various applications, emphasizing the need for further research to optimize their properties and applications.