To study effect of letrozole combined with ethinylestradiol cyproterone for treating infertility women with polycystic ovarian syndrome (PCOS), and to study its influence on the levels of testosterone (T) and estradiol (E2) of the women. Methods: 99 infertility women with PCOS were included in this study and were divided into study group (n=50) and control group (n=49) by random number table method from April 2018 to April 2019. The women in both groups were given metformin treatment, the women in the control group were given ethinylestradiol and cyproterone tablets additionally, and the women in the study group were given letrozole combined with ethinylestradiol and cyproterone tablets additionally. The clinical efficacy, the levels of serum T, E2, luteinizing hormone (LH), and follicle stimulating hormone (FSH), the endometrial thickness on the ovulation day, the number of mature follicles, the cycle ovulation rate, the pregnancy rate, and the incidence of adverse reactions of the women were compared between the two groups. Results: After treatment, the total effective rate (92.0%) of the women in the study group was significant higher than that (73.5%) of the women in the control group. The serum T, E2, LH, and FSH levels of the women in the two groups had decreased significantly, and which of the women in the study group were significant lower than those of the women in the control group. The endometrial thickness on the ovulation day, the number of mature follicles, the cycle ovulation rate, and the pregnancy rate of the women in the study group were all significant higher than those of the women in the control group (all P<0.05). There was no significant difference in the incidence of adverse reactions (6.0% vs. 8.2%) of the women between the two groups (P>0.05). Conclusion: Letrozole combined with ethinylestradiol cyprogesterone tablets for treating infertility women with PCOS has significant effect, which can effectively improve their serum T and E2 levels.