Abstract: It has been widely suggested that poor ability of oocyte cytoplasmic factors to globally erase the epigenetic modifications of a somatic cell is the major reason of the inefficiency of nuclear transfer. In this study, bovine fetal fibroblasts passaged 5 times were seeded into DMEM plus 10% FBS containing 75 nmol·L-1 of TSA for 6, 12, 24 h , respectively. These levels were selected to produce timedependent effects. Cells were subsequently subjected to essay for histone acetylation of H3K18 levels by confocal microscope. The effect of Trichostatin A treatment donor cells on in vitro development of bovine nuclear transfer (NT) embryos which were constructed with bovine fetal fibroblast cells and cell cycle was investigated. These results showed that TSA increased the levels of histone acetylation of H3K18 after bovine fetal fibroblast cells treated with 75 nmol·L-1 TSA for 12 or 24 h(P＜005);75 nmol·L-1 TSA treatment of donor cells for 12 h promoted blastocyst development compared to control (235% vs157%, P＜005) ; Marked difference existed in the percentage of cells at G0/G1 and S stages between treated and control groups(P＜005). It was concluded that TSA enhances the reprogramming in terms of high histone acetylation of doner cells.