Pregnancy is a necessary process in most women’s lives, but pregnancy itself is a very complex physiological process that requires timing, location and harmony. It requires timing, i.e. the woman has normal eggs and the man has normal sperm; location, i.e. the channels for the egg and sperm to meet are open, including the woman’s fallopian tubes, uterus and vagina, and the man can ejaculate normally; and harmony, i.e. the egg and sperm meet and combine to form a fertilized egg that can be planted on the endometrium and grow and develop. These three are intertwined, and the lack of any one of them can lead to infertility. The advent of assisted reproductive technologies such as artificial insemination and IVF has been a boon to infertility patients. However, many patients do not know enough about these two methods of assisted conception, so what is the difference between IUI and IVF? Artificial insemination is the process of optimizing the male partner’s sperm outside the body and injecting it into the uterine cavity through a catheter via the vagina during the female partner’s ovulation. This technique is mainly used in cases of mild oligospermia, liquefaction disorders, sexual dysfunction, genital malformations in the male partner, infertility due to cervical factors in the female partner, infertility due to partial reproductive tract malformations and psychological factors that prevent sexual intercourse, immunological infertility and infertility of unknown origin. The prerequisite for artificial insemination is that the woman’s fallopian tubes are open. IVF, i.e. in vitro fertilization – embryo transfer, is performed by ovulation promotion and egg retrieval, while the male partner’s semen is processed in vitro to simulate the human body environment, so that the egg and sperm combine to form an embryo, which is then transferred back to the female partner’s uterine cavity after in vitro culture to select high-quality embryos. It is mainly used for female partner’s tubal failure, ovulation disorder, endometriosis, male partner’s low spermatozoa, immune infertility and unexplained infertility. In a nutshell, IVF is performed through medication to promote ovulation, egg retrieval and in vitro fertilization, while IUI is relatively simple and only replaces the process of intercourse. IUI and IVF are suitable for different patients and require a treatment plan after a thorough evaluation by the doctor. In general, patients who meet the indications for IUI do not need IVF to help them conceive.