Indications: 1. normal semen but difficulty in ejaculating semen into the vagina during intercourse 2. sperm dysfunction in the female reproductive tract 3. mild abnormalities in semen examination 5 million/ml ≤ sperm count <20 million/ml, semen reduction <2ml, sperm viability <70% 4. immunological infertility 5. unexplained infertility Basic conditions for both male and female: female partner: patent fallopian tubes; uterine development Normal or abnormal but it does not affect the operation of IUI and fetal conception; normal ovarian function, natural cycle or ovulation promotion cycle, ultrasound monitoring can find mature follicles Male partner: semen can be collected in vitro and sperm are present, the more normal the semen examination index, the higher the pregnancy rate of IUI.