The mouse blastocysts were used as a model to study the expression profiles of key genes in mice during the hatching and development of blastocyst and to further analyze the mechanism of pregnancy recognition. The transcriptome of blastocysts at different stages of the hatching process was analyzed. The expression levels of key genes were detected with qPCR. The expression patterns of key proteins were studied with immunofluorescence staining. The results of analyzing the transcriptome showed that the expression of differential genes exhibited two regulatory patterns during the hatching process of mouse blastocysts from expansion， hatching to the completion of hatching. The results of GO analysis and KEGG analysis on the set of genes in the regulatory pattern showed that they were involved in biological processes including immunity and inflammation， cell differentiation， and apoptosis， etc. The results of qPCR showed that the expression of key genes Ptgs1， Lyz2， Il-1α， Cfb and Ccl9 were up-regulated， while Cd36 was down-regulated during hatching of mouse blastocysts， which was consistent with the results of transcriptome analyses. The results of immunofluorescence staining showed that Plac1， Cdx2 and C3 were down-regulated， while Lyz2 and Il-1β were up-regulated during the hatching of mouse blastocysts. It is indicated that the expression of gene exhibits specific dynamics of differentiation and the expression of abnormal gene can lead to hatching at a standstill.