Objective To analyze the clinical efficacy of Metformin combined with Letrozole in the treatment of infertility with polycystic ovary syndrome and its effects on glucose and lipid metabolism, sex hormones, serum adiponectin (APN), monocyte chemotactic protein-1 (MCP-1) and insulin-like growth factor-1 (IGF-1). Methods A total of 84 infertility patients with polycystic ovary syndrome admitted to Beijing Huabo Hospital from February 2019 to February 2021 were selected as the research objects, they were divided into two groups according to random number table method, 42 cases in each group. Patients in the control group were treated with Letrozole, and the patients in the observation group were treated with Metformin combined with Letrozole, all patients were treated for 3 months. The clinical efficacy 3 months after treatment, the changes of glucose and lipid metabolism indexes, sex hormone and serum APN, MCP-1 and IGF-1 levels before and 3 months after treatmen of patients were compared between two groups. Results The total clinical effective rate of patients in the observation group 3 months after treatment was 95.24%, which was higher than that 80.95% of patients in the control group; compared with before treatment, fasting blood glucose (FBG), triglyceride (TG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), serum luteinizing hormone (LH), estradiol (E2), follicle stimulating hormone (FSH) and serum MCP-1 and IGF-1 levels 3 months after treatment of patients in the two groups decreased, the observation group was lower than the control group; while the serum APN levels of patients in the two groupsincreased, the observation group was higher than the control group (all P <0.05). Conclusion Metformin combined with Letrozole has significant clinical efficacy in the treatment of infertility patients with polycystic ovary syndrome, which can improve the glucose and lipid metabolism, sex hormone levels and regulate the correlating cytokines.