The transformation zone of the cervix is the area composed of the junction site of the primitive squamous and columnar epithelium, as well as the physiological squamous and columnar epithelial junction site. The general transformation zone is divided into 3 types, namely type 1 transformation zone, type 2 transformation zone, and type 3 transformation zone. type 1 transformation zone is the original squamous-columnar junction site, and the physiological squamous-columnar junction site are outside the cervical orifice, and the whole transformation zone can be clearly seen through colposcopy. type 2 transformation zone is the original squamous-columnar junction site is visible, and the physiological squamous-columnar junction site may lose into the cervical canal, so The type 2 transformation zone is when part of the transformation zone is not clearly visible and part of it is visible, while the type 3 transformation zone is when neither the original squamocolumnar junction nor the physiologic squamocolumnar junction is visible, due to surgery or atrophy and withdrawal into the cervical canal. The transformation zone is not indicative of any problem, but can only help determine whether cervical lesions have occurred.