Abstract: A antimicrobial peptides- producing lactic acid bacterial strain with broad- spectrum was selected from newborn by the oxford cup agar diffusion method. Based on cell morphological,physiological,biochemical characteristics,Ribo Printer and 16 S r DNA sequence analysis,the strain was identified as Enterococcus faecium.The antimicrobial activity of the fermented supernatant remained by catalase treatment. In addition,the inhibitory activity was lost after treated with trypsin,pepsin and proteinase K. Therefore,the inhibitory substance was preliminary determined as antimicrobial peptide.The antibacterial activity of antimicrobial peptide was not affected by low p H( 2.0~5.0) and the antimicrobial peptide exhibited good thermal stability by treatment from 45 ℃ to 100 ℃for 1 hour. Three amino acid sequences of the antimicrobial peptide were identified by LC- MS / MS and APD database.The antibacterial peptide has great research value.