In this study, we selected gelatin as ECM (extracellular matrix) to support differentiation of mES (mouse embryonic stem) cells into TE (trophectoderm), as gelatin was less expensive and widely used. We found that 0.2% and 1.5% gelatin were the suitable concentrations to induce TE differentiation by means of detecting Cdx2 expression using real-time PCR. Moreover, about 15% cells were positive for Cdx2 staining after 6 days differentiation. We discovered that the expressions of specific markers for TE, such as Cdx2, Eomes, Hand1 and Esx1 were prominently increased after gelatin induction. Meanwhile, the expression of Oct4 was significantly decreased. We also found that inhibition of the BMP (bone morphogenetic protein) signalling by Noggin could promote mES cells differentiation into TE, whereas inhibition of the Wnt signalling by Dkk1 had the contrary effect. This could be used as a tool to study the differentiation and function of early trophoblasts as well as further elucidating the molecular mechanism during abnormal placental development.