Objective:To investigate the correlation between cyclooxygenase-2(COX-2), estrogen receptor (ER), progesterone receptor(PR) and the formation of endometrial polyps and the increased malignant rate of postmenopausal endometrial polyps.Methods:From January 2018 to January 2019, a total of 160 postmenopausal women treated in the People's Hospital of Changxing County were selected and divided into endometrial polyps group(83 cases) and oothectomy group(42 cases), normal menopause group(35 cases) according to different diseases.The levels of COX-2, ER, PR in the three groups were measured.The expression of COX-2 in mesenchymal cells and glandular epithelial cells, the expression of ER in mesenchymal cells and glandular epithelial cells, the expression of PR in mesenchymal cells and glandular epithelial cells in the three groups were compared, and the correlation between COX-2, ER, PR and increased malignant rate of endometrial polyps was analyzed.Results:The positive expression rates of COX-2 in mesenchymal cells and glandular epithelial cells in the endometrial polyps group(16.9%, 30.1%) were higher than those in the normal menopause group(0.0%, 11.4%) and the oothectomy group(4.8%, 7.1%)(χ 2=4.568, 5.806, all P<0.05 ). There were no statistically significant differences in the expression of ER in mesenchymal cells and glandular epithelial cells among the three groups(χ 2=1.333, 1.412, all P>0.05). The expression of PR in mesenchymal cells and glandular epithelial cells in the endometrial polyps group was lower than that in the normal menopause group and the oothectomy group(χ 2=4.890, 5.022, all P<0.05). COX-2 was positively correlated with the increase in malignant rate of endometrial polyps( r=4.335, P<0.05), PR was negatively correlated with an increase in the malignant rate of endometrial polyps( r=-4.256, P<0.05), and ER had no significant correlation with an increase in the malignant rate of endometrial polyps( r=1.203, P>0.05). Conclusion:COX-2 and PR are significantly related to the formation of endometrial polyps and the increase in malignant rate of postmenopausal endometrial polyps, but there is no significant expression of ER.Therefore, the detection of COX-2 and PR levels is beneficial to provide a certain scientific basis for clinical treatment.