Intrauterine insemination (IUI) is a procedure in which the husband’s semen is processed to remove the seminal plasma and concentrate the fluid with motile sperm and injected into the uterine cavity of the patient to help her become pregnant. IUI is indicated for infertility due to immune factors, low sperm count due to male factors, cervical factors, unexplained infertility and endometriosis with patent fallopian tubes. If the husband is always away, frozen stored semen can be used. Women with anti-sperm antibodies in the serum can affect the operation of sperm in the female reproductive tract, sperm-egg union and phagocytes in the reproductive tract have a phagocytic effect on sperm, and semen treatment can reduce or eliminate these adverse effects; patients with weak spermatozoa have a sperm count between 1,000,000 and 2,000,000/ml, an activity rate of <40%, or an increase in deformed sperm, and treatment can increase the sperm activity rate and Concentrate the number of sperm. The cervical mucus is sticky sperm cannot easily pass, affecting sperm upstream, such as severe cervical erosion, ever electrocautery or conical excision, Chlamydia trachomatis infection, post-coital test found no active sperm in the mucus, direct sperm delivery into the uterine cavity can achieve good treatment; patients with endometriosis tubal patency can have intrapelvic adhesions, abnormal tubal peristalsis, sperm entering the abdominal cavity for macrophages to be engulfed These obstacles can be overcome by intrauterine insemination. Intrauterine insemination requires that the female partner is <40 years old and that the fallopian tubes are patent by hysterosalpingography or laparoscopy. The basal body temperature test and ultrasound examination indicate ovulation, and the husband's semen examination and upstream test show that the sperm density and motility can meet the requirements.