The invention discloses antibacterial peptide of bactrocera dorsalis hendel and derivatives and application of the antibacterial peptide. An amino acid sequence of antibacterial peptide is as shown in SEQ ID NO:1; the derivatives of antibacterial peptide are antibacterial active derivatives obtained through modification or antibacterial derivatives formed through substitution, deletion or addition of one or more amino acid residues; obtained antibacterial peptide BH-AMP003 has bioactivity and a wide antibacterial effect, so that antibacterial peptide BH-AMP003 can be applied to preparation of antibacterial products including feed additives, animal drugs, preservatives and medical products such as antibacterial drugs.