CIN3 is an advanced stage of cervical precancer that rarely resolves spontaneously and, according to the guidelines of the American Colposcopy and Pathology Society, should be treated resectively or destructively if the patient is clearly diagnosed with CIN3, regardless of age or whether pregnancy is indicated (except in pregnant women or adolescents). And for recurrent, cervical canal presenting, colposcopically unsatisfactory CIN2/3, or CIN that cannot be graded, treatment with diagnostic excision is specifically recommended. So how extensive should the resection be? According to the literature and our experience, CIN3 should be treated with the main point of excision of the lesion. Usually, the margin of the lesion is marked with iodine, and a tapered excision is made 12.5 px outside of it as an external margin, to a depth of 2 – 62.5 px. The tapered excision can be done by electric knife, laser, cold knife tapered excision, etc. So should the scope be reduced for those who have a pregnancy requirement? The answer is no. For those who have a pregnancy requirement, they should try to maintain the normal physiological function of the cervix as much as possible and try to cut the CIN3 lesion at one time to avoid a second excision. In general, the chance of future preterm delivery after conization is 15% due to partial removal of the cervix.