Abstract: The primers were designed and synthesized according to the reported muscovy duck reovirus(MDRV) M gene in Genbank. M gene in muscovy duck reovirus MW9710 strain were amplified by RT-PCR and went on sequencing and characteristic analysis. M1 genome segment was 2283bp in length, the nucleotide sequence had 99.9% homology with MDRV S14 strain and no more than 74.0% homology with ARV. M1 gene contained only one ORF (13bp~2211bp) that was predicted to encode μA protein of 732 amino acid. M2 genome segment was 2155bp in length, the nucleotide sequence had 99.9% homology with MDRV S14 strain and no more than 69.0% homology with ARV. M2 gene contained only one ORF (28-2058bp) that was predicted to encode μB protein of 676 amino acid. M3 genome segment was 1997bp in length and the sequence had 95.3% homology compared to MDRV 89330, but at most 74% homology with ARV. M3 gene in muscovy duck reovirus contained an ORF(25-1683bp)that encoded a protein of 552 amino acids with a molecular mass of 60.0Kd. but ARV lacked a nucleotide C in 1169bp,that made the ORF (25-1932bp)encode 635 amino acids. The 3'terminal conserved motif was UCAUC-3', but 5'terminal conserved motif was 5'ACUUUUU, 5'UCUUUUU, 5'GCUUUUU in M1,M2,M3 genome segment respectively.