Semen is centrifuged to concentrate the most viable sperm and injected through a tube into the patient’s uterine cavity to help the patient become pregnant. After washing or upstream treatment, it can increase the density of active sperm, reduce or remove prostaglandins, immunologically active cells, anti-sperm antibodies and bacteria and debris in seminal plasma, reduce the viscosity of semen, and promote sperm capacitation and improve sperm fertilization ability; direct injection into the uterine cavity can also avoid unfavorable factors such as anti-sperm antibodies in cervical mucus. Compared with IVF-ET, the IUI technique is simple, safe, inexpensive and less damaging to the patient. If the husband’s sperm is used, it is artificial insemination by husband (AHI), and if the male partner is azoospermic, sperm from a sperm bank must be used, which is called artificial insemination by donor (AID). The cycle pregnancy rate for artificial insemination can be 10% to 15%, which is slightly higher than the natural pregnancy rate. What are the requirements for artificial insemination? Male partner: mild oligospermia, weak semen severe hypospadias, retrograde ejaculation, impotence, premature ejaculation, non-ejaculation, abnormal semen liquefaction, immunological infertility, multifactorial infertility; Female partner: vaginal and cervical stenosis, vaginal spasm, excessive anterior, anterior or retroflexion of the uterus, cervical factors: abnormal post-coital test, immunological infertility, mild endometriosis, unexplained infertility, multifactorial infertility. At least one of the fallopian tubes must be patent.