Abstract: The goat 8~16C stage embryos obtained from in vivo and in vitro was studied using the way of single preimplantation embryo mRNA differential display. Some specific fragments expressed in vivo embryos was found and one of them was selected for further analysis. The result suggested that this fragment displayed high homology (91%) to human mRNA for ribosomal protein L31. The protein encoded by this gene is one element of ribosomal. The integrated structure of ribosomal is essential for the process of protein synthesis, and the ribosomal proteins have the important functions of regulating the gene expression as well.