A semen test reveals the absence of sperm, which we call azoospermia cited. As one of the most difficult to treat infertility, azoospermia had caused profound suffering to patients and numerous problems to doctors.” Failure to find a single sperm in the ejaculated semen for three consecutive times is called azoospermia.” Azoospermia accounts for about 15-20% of male infertility patients and has a wide range of causes, which are summarized into two main categories. One is the dysfunction of the testes themselves, called primary azoospermia or non-obstructive azoospermia. The second is normal testicular spermatogenesis, but due to obstruction of the vas deferens, sperm can not be discharged from the body, known as obstructive azoospermia cited. First, the definition of azoospermia: Where no sperm is found in the routine semen examination, the semen needs to be centrifuged and the sediment taken for microscopic examination, and if no sperm is found in three examinations, the diagnosis of azoospermia can be confirmed. At the same time, patients with non-ejaculation and retrograde ejaculation need to be excluded. The azoospermia classification: Azoospermia can generally be divided into two categories: 1. is the testicular dysfunction itself, called primary azoospermia or non-obstructive azoospermia. 2., is normal testicular sperm production function, but due to obstruction of the vas deferens, sperm can not be discharged out of the body, known as obstructive azoospermia cited. The quantitative determination of serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone is generally required for azoospermia patients. If the FSH measurement value is higher than the upper limit of normal by 2 times, it often indicates testicular spermatogenic dysfunction. Through seminal plasma biochemical analysis, the site of vas deferens obstruction can be initially determined. If the discharged semen is not coagulated, the semen volume is low and the seminal plasma fructose measurement is zero, it indicates seminal vesicle deficiency; if the seminal plasma neutral glycosidase is low, epididymal obstruction should be considered; if the testicular biopsy is normal, obstructive azoospermia should be considered first. If obstructive azoospermia is suspected, vasovasography should be done to observe whether there is obstruction of the seminal tract and to clarify the site of obstruction. Treatment For epididymal tail obstruction and vas deferens obstruction, anastomosis can be done; for ejaculatory duct obstruction, transurethral ejaculatory ductotomy can be done. Azoospermia caused by sperm dysfunction is generally untreatable, and artificial insemination by sperm donor can be chosen.