Differences in gene expression in muscles from Chinese black-boned sheep and local common sheep were investigated using mRNA differential display. One differentially expressed novel gene was identified through semi-quantitative RT-PCR, and the full-length cDNA sequence was then obtained using the rapid amplification of cDNA ends (RACE). The nucleotide sequence of this gene is not homologous to any of the known sheep genes, but it contains an open reading frame encoding a protein of 416 amino acids, which has high homology with matrix metallopeptidase 7 (matrilysin, uterine) (MMP7) of 10 species: bovine (93%), rhesus monkey (75%), human (74%), pig (73%), chimpanzee (73%), dog (73%), horse (72%), mouse (66%), rat (65%), and chicken (53%). Thus the novel gene can be defined as the sheep MMP7 gene. It was finally assigned to GeneID:100192317. The phylogenetic tree analysis revealed that the sheep MMP7 gene is closely related to the bovine MMP7. Our experiment is the first one to establish the primary foundation for further research on the sheep MMP7 gene.