Antimicrobial peptides ( AMPs) are a kind of micromolecular peptides with antibacterial , antivirus and anti-tumor activities.Unlike conventional antibiotics , acquisition of resistance by a sensitive microbial strain against AMPs is surprisingly improbable .AMPs are not widely used clinically due to their toxicity , susceptibility to proteolysis and high manufacturing cost .Researchers have obtained some AMPs with high activity and low toxicity by structure modifications . The molecular design of AMPs as well as their development in the future are reviewed .