Objective To study the relationship between the expression of connective tissue growth factor (CTGF) and matrix metalloproteinase-9 (MMP-9) in ovary and polycystic ovarian syndrome. Methods 52 female rats (6 weeks of age, with regular estrous cycles) were divided into two groups (control group and model group) according to different modeling methods. The control group was given carboxymethyl cellulose by gavage, and the model group was given the same amount of letrozole. The serum and ovarian tissue of the two groups were collected when the estrous cycle of rats was not fixed and had the characteristics of continuity. RIA method was used to determine LH, FSH, E2, PRL, and testosterone, respectively. The endocrine changes of model mice were evaluated and analyzed by PRL, testosterone and other indexes. The expression of connective tissue growth factor and MMP-9 in ovarian tissues was determined and analyzed by immunohistochemical methods using CTGF primary antibody, secondary antibody, third antibody and MMP-9 primary antibody, secondary antibody and third antibody. Results The expression levels of PRL, LH, presinus follicular cytoplasm (CTGF, albumen CTGF, basal membrane cytoplasm of follicle CTGF) and MMP-9 in corpus luteum of the model group were significantly higher than those of the control group (P＜0.05). However, the expression levels of FSH, serum estradiol and MMP-9 in the basal membrane of follicles were significantly decreased (P＜0.05). Conclusion There is a certain correlation between the level of connective tissue growth factor in the ovary and the overexpression of small and medium follicles or ovulation disorder in this disease, and MMP-9 is associated with ovulation disorder in polycystic ovary syndrome