Objective To explore the effect of domoxifen combined with tamoxifen on ovulation in clomiphene-resistant patients with polycystic ovary syndrome. Methods 100 patients who was resistant to CG were randomly divided into two groups:the treatment group (group A) and control group (group B). Oral dosing CC 100mg/d to the patients of group A in the first 3th to 7th days of menses,at the same time,oral dosing tamoxifen 40mg/d in the first 3th to 7th days of menstrual cycle. The dose of CC to group B was same as group A. Beginning to monitor the case of follicular growth during the 8th day of menses. When a ovarian follicle' s diameter beyond 18mm or 2 ovarian follicle' s diameter beyond 17mm, intramuscular injection hCG 10 000IU, sexing after 36 hours later. Observing the two groups of the mature ovarian number,the endometrial thickness, the days of promoting ovulation ,the level of progesterone in serum about the 22th day of menstrual cycle, ovulation rate and pregnancy rate, after injecting hCG.Results The day after injecting hCG, the mature ovarian follicle number,the endometrial thickness, the level of progesterone in serum about the 22th day of menstrual cycle,ovulation rate and pregnancy rate,group A was significantly different from group B( P ＜0.05 ～ P ＜0. 01 ) ,the days of promoting ovulation have no statistically significant differences between the groups (P ＞ 0. 05). Conclusion In the clomiphene-resistant patients with polycystic ovary syndrome,tamoxifen could promote ovulation,improve the effect of CC on the uterus' s anti-estrogen,increase endometrial thickness, elevate ovulation rate and pregnancy rate.