The invention relates to a short peptide. The amino acid sequence of the small peptide is Ile Leu Ser Lys Leu Arg Leu Glu Thr Ala Pro Asn Ile Ser Lys Ala Val Ile Arg Gln Leu Leu Pro Arg Ala Pro Pro Leu Arg Glu. The invention simulates the combination mode of an M propeptide and a C segment, synthesizes the short peptide which can be combined with the C segment, can inhibit the MSTN activity in the animal bodies and promote the growth of the skeletal muscle of livestock, and is simple, convenient, safe and effective when being used for breeding the livestock with more muscles.