Abstract： Objective： To observe the clinical effect of modified Erjia Dihuang tang combined with letrozole tablets for infertility resulting from polycystic ovary syndrome(PCOS) of the kidney deficiency with phlegm-dampness type. Methods：A total of 80 cases of patients with infertility resulting from PCOS of the kidney deficiency with phlegm- dampness type were randomly divided into the observation group and the control group，with 40 cases in each group. The control group was treated with letrozole tablets，and the observation group was additionally treated with modified Erjia Dihuang tang based on the treatment of the control group. The indexes of serum sex hormones， endometrial receptivity and insulin resistance were compared between the two groups before and after treatment；the ovulation rate and pregnancy rate in the two groups were counted after one- year follow- up. Results ： The levels of luteinizing hormone(LH) ， fasting blood glucose(FBG) and fasting insulin(FINS) in serum， homeostatic model assessment of insulin resistance(HOMA- IR)， and pulsation index(PI) and resistance index(RI) in uterine spiral arteries were decreased when compared with those before treatment(P＜0.05)，and endometrial thickness was increased (P＜0.05)，and levels of serum estradiol(E2) were increased(P＜0.05). After treatment，levels of LH，FBG and FINS in serum，HOMA-IR and PI and RI in uterine spiral arteries in the observation group were lower than those in the control group， and endometrial thickness was increased(P＜0.05)； level of E2 in the observation group was higher(P＜0.05). There was no significant difference being found in the comparison of ovulation rates between the two groups(P＞0.05). The pregnancy rate was 47.50% in the observation group，higher than that of 25.00% in the control group(P＜0.05). Conclusion：Modified Erjia Dihuang tang combined with letrozole tablets can significantly improve endometrial receptivity of patients with infertility resulting from PCOS of the kidney deficiency with phlegm-dampness type，correct reproductive endocrine disorders，reduce insulin resistance，and improve pregnancy rate.