Mr. Li is usually optimistic and open-minded, broad-minded and fat, 1.81 meters tall, weighing 126 kg. Recently, Mr. Li encountered a troubling problem: after 2 years of marriage, his wife has not been pregnant, and when he went to the hospital to check his semen, he found that he had severe oligospermia: the sperm density was only 1.6×106/ml, and the forward motion was 6%. Mr. Li thought he was always in good health, but he did not expect his semen to be of good quality. Dr. Liu combined with other test results of Mr. Li and analyzed that this condition had something to do with him being too fat. The body mass index (weight in kilograms divided by height in meters squared) is a measure of the body’s fatness and health, and the normal body mass index is 18.5-25%, more than 30% is obese, and Mr. Li is 38.6%, which is severe obesity. Obesity is one of the factors leading to male infertility, and the reasons are as follows: I. Obese people have too much fat in their bodies, which will produce too much aromatase, leading to an increase in the level of estrogen in the body, thus negatively inhibiting the pituitary gland of the hypothalamus, causing the level of testosterone in the body to fall, resulting in the production of sperm affected; two. Obesity can lead to hypertension, hyperglycemia and hyperlipidemia, also known as metabolic syndrome, modern research shows that metabolic syndrome can affect male gonadal function, leading to sperm production disorders; III. Obesity can also affect male libido and sexual function, such as leading to male erectile dysfunction or ejaculation disorder, thus affecting male reproductive function; iv. Obesity is often accompanied by sleep apnea, which leads to lack of oxygen in the body and affects sperm production and vitality. The treatment of obesity-induced infertility begins with lifestyle correction and weight loss. It has been reported that there is an increase in semen volume, total sperm count, and blood testosterone levels in obese men after weight loss. For obese patients with sleep apnea, uvulopalatopharyngoplasty can be used to improve the hypoxic state of the body. Pharmacological treatment is also a means of treating obesity infertility. For patients with elevated estrogen, aromatase inhibitors such as letrozole can lower estrogen and elevate testosterone levels; if estrogen levels are normal, gonadotropin therapy can be used. For erectile dysfunction caused by obesity, treatment with phosphodiesterase inhibitors can achieve good results. In addition, metformin helps to reduce body weight, lower insulin resistance and increase testosterone levels, which has an improvement effect on semen quality in obese patients. For patients for whom the above treatments are ineffective, assisted reproductive techniques such as artificial insemination, in vitro fertilization-embryo transfer, and single sperm follicular plasmapheresis are the last resort for patients with oligozoospermic infertility. Human semen quality is on a decreasing trend, and besides the effects of environmental pollution and stressful life, more and more people are obese is one of the reasons. Therefore, controlling obesity is not only to prevent chronic diseases, but also an important means to maintain male vitality and virility.