Obesity has become a global disease in recent years, and obesity mostly appears in childhood and is more common in childbearing age. The International Society for Life Sciences defines Chinese adults with a body mass index (BMI) >24 kg/ m2 as overweight according to the characteristics of the Chinese population, and compared with the international standard for obesity BMI >25, Chinese people are more likely to develop metabolism-related diseases at lower BMI levels. Obesity affects human reproductive health in several ways. 30-47% of overweight or obese women have menstrual cycle disorders. Obesity during childhood or adolescence increases the risk of menstrual disorders in women of childbearing age. The relative risk of anovulatory infertility is 1.3 for patients with a BMI between 24-31 km/m2 and 2.7 for those with a BMI >32 kg/m2. Obese anovulatory women have significantly better ovulatory function and pregnancy rates after weight loss. The relative risk of anovulatory infertility in patients with BMI>32 kg/m2 was 2.7. In women with BMI >29 kg/m2, the natural pregnancy rate decreased by 4% for every 1 kg/m2 increase in BMI. On the other hand, obese patients have a high content of lipid droplets in their eggs, which adversely affects egg quality. Even in people undergoing assisted reproductive treatment, obese patients have increased ovulation times, gonadotropin use and cycle cancellation rates due to poor response, while the number of eggs obtained is reduced. In addition, obesity increases the incidence of miscarriage and many obstetric complications, such as placental abruption, gestational diabetes, and hypertensive disorders of pregnancy, and increases the rate of cesarean delivery in obese women. Obesity not only increases birth defects in newborns, but also has longer-term effects on offspring in childhood and adulthood. On the other hand, the incidence of oligo- and hypospermia in men also increases with BMI. Obesity is strongly associated with human reproductive health, and obese women should undergo preconception counseling to clarify weight control protocols, obstetric and neonatal complications, and long-term complication effects in offspring. Lifestyle changes including diet and exercise are the first-line treatment options for obesity treatment. Pharmacological or surgical treatment should be considered only if obesity status does not improve after lifestyle changes.