To study the value of loop electrosurgical excision procedure（LEEP）combined with frozen section examination (FSE) during operation for diagnosis and treatment of cervical intraepithelial neoplasia Ⅲ (CIN Ⅲ)．Methods: The clinical data of 234 patients with CINⅢ after biopsy result who had underwent LEEP and FSE were analyzed retrospectively. The coincidence situation of the results of preoperative biopsy, FSE during operation, and postoperative paraffin pathology examination were compared. Results: The accuracy, the sensitivity, the positive predictive value, and the negative predictive value of diagnosed by pathological margin of 234 unfreezing samples were 98.29% (230/234), 95.2% (80/84), 100% (80/80), and 97.4% (150/154), respectively. The pathology of paraffin samples of 154 cases (65.81%) after operation was completely consistent with that before and during operation. The pathology of paraffin samples of 202 cases was consistent with that of freezing samples, which concordant rate was 86.3% (202/234). There were 16 cases (6.8%, 16/234) with the increased pathological stage diagnosed by the paraffin pathology, which was more than that by preoperative pathology, but was less than that by preoperative pathology. There were 16 cases (6.84%, 16/234) with the increased grade of ICN and pathological stage diagnosed by the paraffin pathology, which included 2 cases had been supplemented with parauterine extensive excision combined with pelvic lymph node dissection and 2 cases (0.85%, 2/234) had experienced secondary operation. Conclusion: Colposcopic LEEP combined with FSE during operation can diagnose and subsequent treat women with CIN Ⅲ rapidly and accurately, which is feasibility．