Abstract： Objective： To observe the clinical effect of the therapy of modified Guizhi Fuling Pills combined with Letrozole on infertility caused by polycystic ovary syndrome. Methods：A total of 96 patients with infertility caused by polycystic ovary syndrome with syndrome of kidney deficiency with blood stasis were selected and divided into the control group and the observation group，with 48 cases in each group. The control group was given Letrozole Tablets for treatment， and the observation group was additionally treated with modified Guizhi Fuling Pills based on the treatment of the control group. With one menstrual cycle as a course of treatment，both groups were treated for three courses. The clinical effects，indexes of sexual hormones，coagulation markers，lipid metabolism indexes and incidence of adverse reactions were compared between the two groups. Results：With follow-up for 1 year after treatment，the total effective rate was 95.83% in the observation group，higher than that of 81.25% in the control group (P＜0.05). After treatment，the ratio of luteinizing hormone (LH) and follicle stimulation hormone (FSH)，and levels of serum LH，testosterone (T)，fibrinogen (FIB)，total cholesterol (TC)，low density lipoprotein cholesterol (LDL-C) and triglyceride (TG) in both groups were decreased when compared with those before treatment (P＜ 0.05)， and the ratio of LH/FSH and levels of serum LH， T， FIB， TC， LDL- C and TG were lower than those in the control group (P＜0.05). The serum prothrombin time (PT) and thrombin time (TT) in both groups were increased when compared with those before treatment (P＜0.05)， and the serum PT and TT in the observation group were longer than those in the control group (P＜0.05). The levels of serum high density lipoprotein cholesterol (HDL-C) in both groups were increased when compared with those before treatment (P＜0.05)，and the serum HDL-C level in the observation group was higher than that in the control group (P＜0.05). The incidence of adverse reactions was 8.33% in the observation group and 12.50% in the control group，there being no significance in the difference (P＞0.05). Conclusion：The therapy of modified Guizhi Fuling Pills combined with Letrozole has a definite curative effect on infertility caused by polycystic ovary syndrome，which can regulate the disorder of sexual hormones，and improve the coagulation markers and lipid metabolism indexes with good safety.