Liraglutide, a hypoglycemic drug, can reduce weight and improve insulin resistance while stabilizing blood glucose metabolism without increasing the risk of hypoglycemia, and has been approved by the State Food and Drug Administration of China and the US Food and Drug Administration for the treatment of obesity. Polycystic ovary syndrome (PCOS) is the main cause of female anovulatory infertility, and it is also a high-risk group of obesity. Previous studies have suggested that liraglutide improves glucose metabolism, body weight, and inflammation levels in obese women with PCOS, and improves sex hormone profiles and menstrual cycles, possibly contributing to increased fertility. Therefore, this project intends to test the following hypothesis through a large sample randomized controlled trial in obese and infertile PCOS women who are assisted by in vitro fertilization-frozen embryo transfer (IVF-FET), using liraglutide before transplantation to reduce weight can improve the live birth rate of assisted reproduction.