Abstract: Polycystic ovary syndrome （PCOS） is the most common endocrine and metabolic disorder in fertile-aged women. PCOS，a highly heterogeneous disease in clinical feature，is one of the main causes of infertility due to anovulation，which affects 5% to 10% of fertile-aged women. Obesity is strongly associated with the PCOS. There are about 50% of PCOS women with overweight or obesity，most of them being abdominal obesity. Obesity is related to a series of metabolic disorders，especially hyperinsulinemia with insulin resistance and hyperandrogenism，which play a pivotal role in the pathophysiological mechanisms of PCOS. Obesity can independently exacerbate insulin resistance and hyperandrogenism，which lead to the high risk of type 2 diabetes and cardiovascular disease in obese PCOS women. In addition，hirsutism，acne and infertility，the typical clinical manifestations，could cause the increasing depression and anxiety in PCOS women.

Key words: Polycystic ovary syndrome, Obesity, Leptin, Insulin resistance, Hyperandrogenism