Objective  To investigate the role of inner cell mass (ICM) in decidualization using decidua induced by two-cell embryos or tetraploid embryos through tubal embryo transfer.   Methods  Tetraploid embryo, as the inner cell mass-deficient embryo, were produced by electrofusion of mouse 2-cell embryos. Decidua was induced by 2-cell embryos or tetraploid embryos through tubal embryo transfer. Decidua induced by 2-cell embryos was employed as a control. Morphologic and implantation site of decidua were compared between two-cell embryo-induced decidua and tetraploid embryo-induced decidua. The differentially expressed microRNA (miRNA) was screened by high-throughput sequencing. The target genes of differentially expressed miRNA in two groups were screened for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).   Results  Tetraploid embryo-induced decidual tissue and 2-cell embryo-induced decidual tissue were very similar at the implantation site, but there were significant differences in decidual morphology. There were 16 miRNAs differentially expressed in decidua of the two groups, of which 11 miRNAs（miR-466f-3p，miR-302 d-3p，miR-466i-5p，miR-465c-5p, miR-302a-5p, miR-7068-3p, miR-741-3p, miR-302a-3p, miR-433-5p, miR-144-5p, miR-878-5p）were up-regulated in tetraploid embryo-induced decidua and 5 miRNAs（miR-690, miR-193b-5p, miR-147-3p, novel_327, miR-363-3p）were down-regulated in tetraploid embryo-induced decidua. Bioinformatics analysis showed that the target genes played function such as protein binding and ion binding, and mainly involved in cyclic guanosine monophosphate-protein kinase G(cGMP-PKG) signaling pathway, estrogen signaling pathway, vascular endothelial growth factor (VEGF) signaling pathway and so on.   Conclusion  ICM plays an important role in decidualization.