Abstract: Mitochondria, as one of the most important organelles, provides energy for cellualar events. Mitochondria DNAs (mtDNAs) are a set of the genetic materials except for the nuclear genome. The shape and distribution of mitochondria vary with the oocyte maturation and early embryo development. The mutations of mtDNAs and the change of copy number were related to the outcomes of embryonic development. It was found that the growing mtDNA mutations caused the increased copy number of mtDNAs, and that the increased copy number of mtDNAs in blastocyst brought the higher success rate of embryo transfer. It is known that a high proportion of oocytes can not be successfully fertilized or developed to the high-quality embryos despite being chromosomally and morphologically normal. Some embryos with morphological high-quality are fail to be implanted successfully. It is important to increase the efficiency of embryo transfer by improving the oocyte quality from the perspective of mitochondria for the assisted reproductive technology (ART).

Key words: Mitochondria, DNA, Mitochondrial, Embryonic development, Oocytes, Reproductive techniques, assisted