Abstract: Objective: To investigate the clinical value of loop electrosurgical excision procedure(LEEP) in patients with severe cervical intraepithelial neoplasia(CIN Ⅲ) before hysterectomy.Methods: Seventy patients with CIN Ⅲ diagnosed by colposcopy were treated with LEEP before hysterectomy.The pathological differences between colposcopy,LEEP edge tissue and total hysterectomy tissue were compared.Results: The disaccord rate of the pathological results between colposcopy and LEEP edge tissue was 28.57%,and the pathology upgrading to infiltrating carcinoma in 5 cases were found,the upgrading rate of which was 7.14%.Thirty-nine cases were diagnosed chronic cervicitis after hysterectomy,and the normal rate was 55.71%.Among the 50 positive LEEP edge cases,23 cases were positive after hysterectomy,the positive rate of which was 46.00%.Among the 20 negative LEEP edge cases 8 cases were posititve affter hysterectomy after hysterectomy,the positive rate of which was 40.00%.The difference of the residual lesions risk of uterus between the positive and negative LEEP edge patients was not statistical significance(P>0.05).Conclusions: The multi-point biopsy under colposcope has the possibility of missed diagnosis in cervical lesions.The diagnostic LEEP in CIN Ⅲ patients should be implemented before total hysterectomy,otherwise hysterectomy is risk.