Disclosed is an antimicrobial peptide having an amino acid sequence of formula presented as (P1)M(nA1X1X2)N(P2)X, wherein P1 is selected from the group consisting of basic amino acids including Arg and Lys A1 is selected from the group consisting of aromatic amino acids including Trp, Phe and Ala X1 is selected from the group consisting of basic amino acids or nonpolar amino acids, including Arg, Lys, Val, Leu, Ala and Ile X2 is selected from the group consisting of basic amino acids or nonpolar amino acids, including Arg, Lys, Val, Leu, Ala and Ile P2 is selected from the group consisting of basic amino acids including Arg and Lys and the numbers of M and X are respectively 0˜2 when N>2, A1 is Ala and the Ala residues are less than N−2.
