The present invention relates to a new antibiotic peptide and a usage thereof, which are derived from ribosomal protein L1, RPL1 of Helicobacter pylori. Specifically, the antibiotic peptide comprising the amino acid sequence of SEQ. ID. NO:1 derived from ribosomal protein L1, RPL1 of Helicobacter pylori is substituted with a Phenylalanine, which is situated at the first and the eighth position from the antibiotic peptide, or in addition an Asparagine, which is situated at the thirteenth position of the antibiotic peptide, is substituted with lysine, wherein the produced peptides have maintained more decreased cytotoxicity when comparing to the existing antibiotic peptides and can be used as a safe antibiotics by showing more antibacterial activity.