Chiari malformation refers to the various anomalies of the hindbrain and the craniovertebral junction and often has the feature of the cerebellar tonsillar descent through the foramen magnum. At present， no clear consensus has been reached on the selection of surgical procedure. Although different surgeons have different surgical procedures， the goal of surgery remains the same， i.e.， alleviating brainstem compression， restoring the normal pattern of cerebrospinal fluid flow in the foramen magnum area， and reducing the size of syringomyelia. This article reviews the classification， clinical manifestations， diagnosis， and surgical treatment of Chiari malformation， especially Chiari malformation type I.