There are 2 types of azoospermia: obstructive azoospermia (OA) and non-obstructive azoospermia (NOA). Obstructive azoospermia is familiar to everyone. The testes have spermatogenic function but cannot discharge through the vas deferens, such as epididymal obstruction, vas deferens obstruction and ejaculatory duct obstruction, among which there are acquired causes such as epididymal obstruction due to epididymitis, vas deferens obstruction due to vasectomy, and also obstruction caused by congenital causes such as congenital vas deferens and seminal vesicle defect. Some obstructive azoospermia can be treated by microanastomosis, such as epididymal obstruction and partial vas deferens obstruction. Other obstructions such as spermatophore agenesis and distal vas deferens obstruction cannot be treated by anastomosis, but because of the presence of sperm in the testes it is possible to obtain a child belonging to both spouses with the help of assisted reproduction techniques. However, non-obstructive azoospermia is a different story. Non-obstructive azoospermia is azoospermia due to various causes of testicular spermatogenic dysfunction. Since it is difficult to find sperm through conventional methods, it is not possible to use the husband’s sperm for natural conception or assisted reproduction. Non-obstructive azoospermia, which accounts for 60% of azoospermia, is more common than obstructive azoospermia, but is more difficult to treat. There are many causes of non-obstructive azoospermia: hypothalamic pituitary lesions, commonly congenital hypogonadism; genetic causes, such as Crohn’s disease, Y chromosome microdeletion; testicular lesions, such as cryptorchidism, mumps causing orchitis, testicular failure after radiotherapy, spermatogenic arrest, and only supportive cell syndrome. There are more methods to diagnose non-obstructive azoospermia, commonly used are physical examination, sex hormone test, chromosome test, inhibin B test, testicular biopsy, etc. The small size and soft texture of the testes found on physical examination generally suggest abnormal testicular spermatogenic function. Abnormally elevated follicle stimulating hormone (FSH) in sex hormones often indicates testicular spermatogenic dysfunction, and low inhibin B also indicates low testicular spermatogenic function. Chromosomal examination can detect some genetic disorders such as Crohn’s disease and Y chromosome microdeletion. Testicular biopsy is the most direct and accurate method to understand testicular spermatogenic function, but it is invasive. In the past there was little treatment for non-obstructive azoospermia, and because it was difficult to obtain sperm from the testes, assisted reproduction through sperm banking for donor sperm or adoption through civil authorities was the only way for couples to obtain a child that was biologically fully owned by both partners. With the development of microsurgery technology, it is now possible for some patients to obtain sperm through microscopic testicular sperm retrieval for assisted reproduction and obtain a child that biologically belongs to both spouses. Microscopic testicular sperm retrieval has been performed abroad for nearly 20 years, with a success rate of 40-60%, but this technology has been performed in China for a very short period of time, and very few units can perform this technology. Microscopic testicular sperm retrieval, which has been performed in China in recent years, has a success rate of over 40%, enabling some patients with non-obstructive azoospermia to obtain their own children. The success rate of sperm retrieval is related to the pathology of the testes. Generally speaking, patients with spermatogenic arrest and hypospermatogenic function have a higher chance of obtaining sperm, and those with atrophied testes also have a relatively higher chance of obtaining sperm. Although the success rate of sperm retrieval is not very high, it is an attempt for those who want to obtain a child that is genetically theirs.