【Abstract】Objective To investigate the reasons of misdiagnosis of endometrial polyps by ultrasonic diagnosis and improve the diagnostic accuracy of transvaginal ultrasound for endometrial polyps.Methods 210 patients suspected endometrial lesion were treated with American GE company LOGIQE9 color Doppler ultrasonic diagnostic apparatus. The uterine size, intima thickness, anomaly pattern and blood flow were observed. The misdiagnosis reasons were analyzed with ultrasonic and pathologic diagnosis.Results Of 210 patients, there were 147 cases with endometrial polyps, 44 cases with simple endometrial hyperplasia, 10 cases with endometrial hyperplasia and endometrial polyps, 4 cases with endometrial inflammation, 3 cases with submucosal myoma of uterus and 2 cases with endometrial carcinoma diagnosed with ultrasonic. There were 145 cases with simple endometrial polyps, 7 cases with simple endometrial hyperplasia, 7 cases with endometrial inflammation, 4 cases with endometrial carcinoma, 3 cases with submucosal myoma of uterus and 44 cases with endometrial hyperplasia and endometrial polyps diagnosed with surgery and pathology. The coincidence rate of ultrasound diagnosis was 80.5% and misdiagnosis rate was 19.5%. The main factors of misdiagnosis were combined with other diseases, unappropriate check period, atypical image, intrauterine device and other inspection conditions.Conclusion Transvaginal color Doppler ultrasound should be excluded to avoid the causes of misdiagnosis.