In recent years, researchers who caused widespread concern, the biological characteristics of the people of this enzyme, physiological function, expression and regulation and other aspects of a better understanding, but is not yet full mRNA of sheep CTSB experimental evidence of a long sequence and protein structure, it is not clear between CTSB activity and sheep oocyte developmental competence relevant, these would have to be carried out in-depth research. For this reason, this study intends to clone sheep CDS CTSB gene sequence and predicted amino acid sequence of the nucleotide sequence and the physical and chemical properties and protein structure in order to provide important theoretical basis for future research on sheep CTSB's. Meanwhile, research in adult sheep and lambs sheep COCs in CTSB activity variation and differences in vitro maturation, and in vitro oocyte maturation was added cysteine protease inhibitor E-64 inhibitory effect of CTSB activity reveals CTSB activity in sheep COCs effect on oocyte developmental competence aims to provide a theoretical basis and technical measures to improve the production efficiency of sheep embryos in vitro, and to fill research on sheep CTSB activity affect oocyte developmental competence gaps.