Objective:To investigate the effect of letrozole tablets combined with ethinylestradiol and cyproterone acetate tablets on TIMP-1,CTGF and serum sex hormone levels in patients with polycystic ovary syndrome infertility.Methods:A total of 110 patients with polycystic ovary syndrome-related infertility were divided into a control group and a combined group based on different treatment regimens,with 55 cases in each group.The control group was treated with ethinylestradiol and cyproterone acetate tablets,while the combined group received letrozole tablets in addition to the treatment used in the control group,for a total treatment period of 3 months.Improvement of clinical symptoms,serum factors,serum sex hormones,adverse effects,ovulation rate,pregnancy rate,ovarian volume,follicle number and endometrial thickness were recorded and compared between the two groups.Results:The improvement rate of clini-cal symptoms in the combined group was higher than that in the control group(P＜0.05).After treatment,the levels of matrix metallo-proteinase-9(MMP-9),MMP-9/tissue inhibitor of metalloproteinase-1(TIMP-1)and follicle-stimulating hormone(FSH)were higher in the combined group than in the control group,and the levels of TIMP-1,connective tissue growth factor(CTGF),luteinizing hormone(LH)and estradiol(E2)were lower than those in the control group(P＜0.05).There was no significant difference in the incidence of adverse reactions between the two groups of patients compared with each other(P＞0.05).Ovulation and pregnancy rates were high-er in the combined group than in the control group(P＜0.05).After treatment,ovarian volume and follicle count levels were lower and endometrial thickness was higher in the combined group than in the control group(P＜0.05).Conclusion:Compared with treatment with ethinylestradiol cyproterone tablets alone,combined letrozole tablets for the treatment of infertility in polycystic ovary syndrome has a definite efficacy,which can effectively improve the imbalance of MMP-9/TIMP-1 and the hormone level of the gonadal axis,and facili-tate the regulation of the level of CTGF,which can help to improve the ovulation and pregnancy rate.