Patients with polycystic ovary syndrome (PCOS) have impaired follicular development and maturation. Ovarian granulosa cells play an important regulatory role in the initiation, growth and development of primordial follicles, in which the mitochondria of granulosa cells are involved in the regulation of cell cycle, metabolism, and signal transduction, and provide energy support for oocyte meiosis, fertilization, and up to early embryonic development through energy metabolic pathways. Studying the mitochondrial function of granulosa cells is one of the best non-invasive methods to study the pathological mechanisms in PCOS patients and to evaluate oocyte quality and embryonic developmental potential. A large number of evidences have shown that PCOS is associated with mitochondrial dysfunction in ovarian granulosa cells by mechanisms including altered mitochondrial DNA(mtDNA) copy number and mutations in the mtDNA gene. Some studies have explored the improvement of mitochondrial function in PCOS granulosa cells to improve the impaired follicular development and maturation in PCOS. Therefore, the relevant research progress in recent years have been reviewed in present paper about mitochondrial dysfunction in PCOS granulosa cells, for exploring the mechanism of mitochondrial dysfunction in PCOS granulosa cells, and the ways and methods of improvement.