Objective: To investigate correlation of pregnancy rate through intrarauterine insemination (IUI) with the ratio of normal sperm and total motile spermatozoa number (A and B). Methods: A retrospective study was carried out with the IUI data of 330 cycles between January 1st and August 31st in 2017 to compare the effects of the ratio of normal sperm and total motile spermatozoa number (A and B) on the pregnancy rates of IUI. Results: a) For patients with normal sperm ratio less than 6%, their clinical pregnancy rate of IUI was significantly different from those with normal sperm ratio between 6% and 10%, or not less than 10% (p<0.05); b) during the treatment cycle, the clinical pregnancy rates of patients whose total motile spermatozoa numbers were not less than 10x106 and those whose total motile spermatozoa numbers were less than 10x106 were 21.6% and 9.2% before and after ovulation, and the difference had statistical significance (p<0.05); for those whose total motile spermatozoa numbers before ovulation were not less than 10x106, and after ovulation were less than 10x106, their pregnancy rate was 14.8%, which was also significantly different from those rates above (p<0.05). Conclusion: a) A high clinical pregnancy rate can be attained in IUI for those whose ratio of normal sperm is not less than 6%; b) IUI requires that seminal fluid should contain at least 10x106 sperms in total motile spermatozoa number, and the inseminations before and after ovulation are similar in importance.