Abstract: Cumulus oocyte complexs (COC) were recovered from abattoir cow ovaries collected from slaughterhouse.Then,They were matured and fertilized in TCM199 with 10% BCS.Later on,the one cell embryos were cultured in two culture systems:1)modified TCM199 over a buffalo rat liver (BRL) monolayer co-culture;2)Two stage semi-defined culture system ［hamster embryo culture medium with 11 amino acids (HECM-6) followed by tissue culture medium 199+10% bovine calf serum］.The results showed that HECM-6/mTCM199 system could improved embryo development to the morula or blastocyst stage higher (50%) than that in BRL/mTCM199 system (41%,P<0.01).This results suggested that HECM-6/mTCM199 two-stage semidefined culture system could provide a significant benefit for the early bovine embryo development,which might be related with glucose concentration and amino acids components in the medium.