Research description: Since the emergency of  antibiotic resistant microorganisms, the search for novel antimicrobial materials has become an urgent issue. The antimicrobial peptides separated from biological organism firstly, and which also could be assembled on Rink amide resin by solid-phase synthesis method using Fmoc chemistry while their chains are not too large. Furthermore, because microbial membrane generally has negative net charges which could be attracted by cationic residues, antimicrobial peptides are cationic often. Cationic antimicrobial peptides contain positively charged residues, approximately 50% hydrophobic residues and chain length ranging from 12 to 50 residues. We could design different sequence of antimicrobial peptides using nature amide acid and study their antimicrobial mechanism.