Objective：To explore the expression rules and potential role of mmu-miR-106b in the endometrium mouse during embryo implantation. Methods：Real-time PCR and in situ hybridization were used to detect the expressions of mmu-miR-106b in the en－dometria of pregnant mice on d4，d5 and d6. MTT and flow cytometry were performed to understand its roles in endometrial stromal cell proliferation，cycle and apoptosis after endometrial stromal cells being transfected with mimics and inhibitor. Western blot was car－ried out to predict the potential target genes of mmu-miR-106b by combining anticipated algorithms. Results：Expression of mmu-miR-106b in the endometria on d6 was lower than that on d4（P=0.039） and there was no significant difference in mmu-miR-106b expression between implantation sites and inter-implantation sites of pregnant mice on d5（P=0.606）. Mmu-miR-106b was located in endometrial stromal cells. Increased mmu-miR-106b could promote cell proliferation and reduced mmu-miR-106b would increase cell apoptosis. Related target genes of nucleophosmin1，tumor susceptibility gene 101（Tsg101） and phosphatase and tensin homolog deleted on chromosome ten were achieved by miRGen，Targetscan and Pictar screening and expression of Tsg101 was regulated by mmu-miR-106b in endometrial stromal cells of pregnancy mice（P=0.042）. Conclusions：Mmu-miR-106b may play an important role in the proliferation of endometrial stromal cells during embryo implantation process by targeting Tsg101.