Abstract: The effect of donor cell cycle, cell hypotonic treatment and recipient oocytes meiosis phase on development of bovine somatic cell nuclear transfer embryos was studied in the present experiment. Oocyte intraplasmic nuclear injection was used as embryo reconstruction method. The results indicated that: There was no significant effect of culturing bovine skin fibroblasts with 0.5% FBS media (attached quiescent cell) on the development of bovine nuclear transfer embryos as compared with nonquiescent cell (P>0.05).Treatment of donor cells with 0.1% sodium citric acid 20 s before nuclear injection was beneficial for cell membrane breakdown and nuclear dissociation, as a result , the nuclear transfer embryos development rate to 8/16-cell stage and blastocytes was significantly higher than control(P<0.01).It was found that donor cells suspended in 0.5% FBS TCM199 3 d (suspended quiescent cell) could make it easily to dissociate nuclear without hypotonic treatment, and development ability of the nuclear transfer embryos was also promoted slightly. The TⅡ oocyte (activation before nuclear injection)or MⅡoocyte (activation after injection) did not significantly affect the development of nuclear transfer embryos. Our findings suggest that donor nuclear dissociation efficiency was crucial to the sucsses of oocyte intraplasmic injection, suspension quiescence was a proper donor cell treatment method,both TⅡoocytes and MⅡ oocytes could be used as recipient.