Abstract: As one of the important organelles in cells, mitochondria is referred as "energy factory" and it generates adenosine triphosphate (ATP), which is involved in cell growth, differentiation, proliferation, apoptosis, signal transduction, cell activity, etc.In human body, mitochondria can be found most abundant in oocyte, and it provides energies for the maturation of human oocyte, fertilization and development of early embryo. While, if the mitochondrial function is impaired, it will lead to aging of oocyte, pregnancy failure and decrease of human assisted reproductive success rate. The distribution and ultrastructure of mitochondria, mitochondrial membrane potential and mitochondrial DNA mutations or copy are summarized in this article, which has great significance in improving the assisted reproductive success in older women.