Antimicrobial peptides (AMPs) are produced by a wide range of organisms and serve as their natural defenses against infection caused by bacteria, viruses and fungi. Because of the positively charge and amphipathic structure, AMPs kill target cells through diverse and complex mechanisms once in a target membrane and these special mechanisms are considered to be the critical factors for the less tendency of drug resistance development. Thus AMPs may become a new generation of promising antimicrobial agents in future anti-infection application. Additionally, AMPs can also be used in food industry and agriculture. On the basis of discussing the structural features, action mechanisms and sources, the applications of AMPs were reviewed in this paper, including in food industry, feedstuff, cultivation of disease-resistant transgenic plant, cultivation of transgenic animal, and aquaculture, especially the patented applications.