There are various methods of classifying anal fissures, which are not quite uniform, as follows: 1. Phase II classification method: divided into acute (phase) anal fissures, chronic (phase) anal fissures. 2.Three classification methods: Phase I anal fissure (for simple anal fissure), Phase II anal fissure (for ulcer-forming phase), and Phase III anal fissure (with 3 – 5 characteristics). 3.Four classifications: divided into four types of anal fissures: simple, ulcerative, old, and secondary. 4.Five types of classification method: divided into five types of anal fissures: stenotic, prolapsed, mixed, fragile, and symptomatic. 5.Type II classification method: In 1975, at the first national anal academic conference in China, anal fissures were divided into two types, simple anal fissures and old anal fissures, according to clinical practicality, which is also the most used classification method in clinical practice nowadays, and their pathogenetic characteristics and pathological changes are as follows: Simple anal fissures Also called early anal fissures. It is characterized by short duration, fresh fissures, chronic ulcers not yet formed, no sentinel hemorrhoids, and less painful cases. Old anal fissure Characterized by the formation of anal canal ulcers with sentinel hemorrhoids, hypertrophic anal papillae, hyperplasia of the pectineal band, and periodic anal pain. The classification of simple anal fissure and old anal fissure is now widely accepted by anorectal physicians and guides clinical work.