The semen will be washed and processed to remove the dead spermatozoa, leukocytes, antibodies and other components in the seminal plasma and semen, and good quality spermatozoa will be selected to be injected into the uterine cavity through the catheter during the female’s ovulation period, which will have the function of selecting the best spermatozoa; it is mainly suitable for the following patients: 1) moderate oligozoospermia and weak spermatozoa; 2) seminal fluid is not liquefied; 3) there are antibodies in cervical mucus or semen; 4) unexplained infertility; 5) the husband’s impotence and premature ejaculation; and 6) the woman’s tubes need to be smooth and there is ovulation.