Background: Anti-Mullerian hormone (AMH) is vital in the pathophysiological process of polycystic ovary syndrome (PCOS). The exact relationship between obesity and insulin resistance (IR) with AMH levels remains unclear. Methods: A retrospective, single-center cohort study of 220 women with PCOS who underwent physical, endocrine, and metabolic assessments were performed. Patients were grouped by age, body mass indices (BMI), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and different phenotypes. Pearson correlation analysis assessed the correlation between AMH and HOMA-IR, BMI, and other PCOS indicators, and multiple linear regression analysis was performed to determine factors influencing AMH. Results: In 220 patients with PCOS, serum AMH levels decreased with age and were significantly higher in the IR group than in the non-IR group (P < 0.01). AMH increased significantly in anovulatory patients with hyperandrogenemia and/or polycystic ovary, with no significant difference between obese and non-obese individuals. AMH levels correlated positively with luteinizing hormone (LH), LH/follicular stimulating hormone (FSH), testosterone, fasting insulin (FINS), and HOMA-IR levels; negatively with age and BMI levels (P < 0.05) and weakly with fasting plasma glucose in the classical PCOS phenotype (r=0.148, P < 0.05). Regression analysis showed that age, testosterone, FINS, LH, LH/FSH, and BMI influenced AMH levels (P < 0.05). Conclusion: Chinese women with PCOS-IR showed associations with greater AMH levels. AMH levels correlated positively with HOMA-IR levels and negatively with BMI. AMH combined with BMI and HOMA-IR levels may help determine PCOS severity.