Abstract: This study aimed to assess the effect of a differentially expressed gene BMP6 screened by SSH on twining trait of Mongolian Sheep and its underling mechanism. The mRNA expression pattern of BMP6 gene in ovarian tissues of multiparous and uniparous Mongolian ewes on the 0^th,5^th,10^ th,15^ thday of oestrum were determined and statistically compared by RT-qPCR. The results showed that during a whole estrous cycle,the mRNA expression profile of BMP6 gene in ovarian tissues of multiparous and uniparous Mongolian ewes exhibited a similar trend of change： on the 0thday of oestrum,the lowest expression level of BMP6 gene was observed,and the highest expression level was observed on the 10 ^thday of oestrum（P〈0.05）; on the 0^thand 10^ thday of oestrum,the mRNA expression of BMP6 gene in multiparous Mongolian ewes was significantly higher（P〈0.05） and very significantly higher（P〈0.01） than that of single-lamb Mongolian ewes,respectively. The obtained results demonstrate that BMP6 is a candidate gene for twining trait of Mongolian Sheep.